There are many ways that painful lessons from the Iraq war have been shaping or will come to shape Obama's Syria policy. Here are two I have not seen discussed much yet:

1. The public punishes policy failure even if it supported the policy initially. Bush's Iraq policies were very popular at the outset. Over time, however, the policies looked less and less successful, and by the darkest days of the war, it looked like the American mission might end in a fiasco. The downward policy trajectory contributed directly to a downward trajectory in public opinion. Yes, there were other reasons -- such as the failure to find WMD -- but the negative fortunes of the war were significant. The fact that large majorities of the public approved of the invasion at the outset did not protect the policy when the war turned south.  

Obama faces precisely this risk on Syria. His current policy of not intervening decisively is popular enough -- the polls show at best modest support for military intervention if WMD has been used and at worst profound reluctance about shouldering additional burdens in the region. Obama, in his ambivalence, has the comfort of being aligned with the public today. But this is a cold comfort, since his policy is failing, every bit and perhaps more so than Bush's Iraq policy during the war's darkest days. Once the public concludes that Obama has failed in Syria, it will not matter much that they initially supported the policies that yielded this failure.

2. Doing the right thing belatedly can rescue the policy without restoring public support for the policy. President Bush turned around the Iraq War by authorizing the surge in 2007. This came late in the war but not too late to turn Iraq from a trajectory of failure to something much better. The surge not only reversed the situation in Iraq, it also changed the political reality at home. Iraq went from being a seething issue that was dominating the political stage to an issue largely devoid of political sting. By the time President Obama took office, the political pressure had been so drained from the Iraq issue that he had a virtual free hand to conduct Iraq policy as he saw fit, jettisoning campaign promises and rhetoric along the way. However, the surge came too late to change the public's overall estimation of the Iraq war. Today clear majorities deem it a mistake, not worth the cost -- and at best a "stalemate," not a "victory" (albeit it neither a "defeat"). Had the surge and its fruits come earlier in the course of the war when support for the war was higher, perhaps the surge would have been able to do more than simply take the political sting out of the war -- it might even have convinced more of the public to stick with their initial support.

Obama seems to be inching toward intervening more aggressively in Syria. At this point, the prospects for that intervention look bleak. But even if the supporters of this option are right, and it is not too late for American action to decisively shift U.S. Syria policy toward something less than a fiasco, it may be too late for the public to see Syria as a success and to credit President Obama accordingly.

Of course, President Obama, like President Bush before him, should do what is in the best interests of the country regardless of the impact on public opinion. But political White Houses do care about political consequences, and in that regard the lessons from Iraq are bleak.

As Syria descends further into the maw of a sectarian civil war fueled by militant islamism  -- and Iraq teeters on the brink of it -- the options for American foreign policy look increasingly grim. The core pillars of Obama's regional strategy have crumbled. The tides of war are not receding, and rather than ending wars "responsibly" so as to "pivot" to Asia, it looks increasingly clear our national interests in the region are in serious jeopardy.

Along the way, events in the Middle East have put in jeopardy one additional thing, one cherished by a certain class of foreign policy pundits: the appeal of "offshore balancing." Offshore balancing is the favored approach of academic realist theory and theorists who believe the United States has too often intervened militarily over the years. 

Offshore balancing purports to offer a middle ground between pure isolationism, which pretends that the United States has no interests worth defending abroad, and the interventionism that has led the United States into costly military conflicts abroad. Offshore balancing involves defending U.S. interests through indirect means, such as providing arms to certain local partners who, it is hoped, will protect U.S. interests on our behalf, and by using other tools of influence to shape local behaviors. 

As a general rule, American foreign policy practitioners have found offshore balancing an unreliable pillar around which to build a global strategy, but it is popular among academics like Christopher Layne, John Mearsheimer, and Stephen Walt.

In fact, it was reading some of Walt's posts separately critiquing efforts to buy influence in Afghanistan and proposals to arm the Syria rebels so as to avoid direct military intervention by the U.S. military that got me thinking again about the wide gulf between the appeal of offshore balancing among some academic theorists and its spotty record in real-world policy.

Perhaps unwittingly, Walt makes a strong case for why offshore balancing is unlikely to work well in protecting U.S. interests in these areas. Walt is unsparing in his critique of the alleged covert program to buy influence in Afghanistan, which he derides as "sleaze" and as a likely culprit in what he predicts will be failure in Afghanistan. Likewise, he argues that providing arms to Syrian rebels will not provide much influence over them, and so the United States should not go down that path. What Walt fails to do is reflect on how his critique of these policies leads logically to a deeper critique of offshore balancing -- for the very steps he is deriding as leading to failure are the core elements of any long-term offshore balancing approach to these challenges. 

Maybe it is a bit unfair to treat Afghanistan as a case of offshore balancing. After all we have been "onshore" in force for over a decade now. However, even offshore balancers recognize the need for episodic military involvement, which is what distinguishes them from pure isolationists. An offshore balancing approach to Afghanistan would have been an extreme version of the light-footprint posture favored by Defense Secretary Donald Rumsfeld: massive punitive action followed by extensive efforts at buying influence among local warlords. This is precisely what John Mearsheimer at the time endorsed as a policy of  "open wallets." Offshore balancers reject the costly heavy footprint approach of counterinsurgency because they believe the United States can more effectively achieve its objectives through a light footprint. Going forward, what else could the offshore balancing prescription for Afghanistan offer if not a reliance on bribery and diplomacy?

It is absolutely fair to label Obama's current Syria policy as an attempt at offshore balancing. The administration has been resolute in avoiding an on-shore commitment in Syria, even to the extent of revising its own red-lines regarding Syrian WMD, and President Obama doubled down on this in his press conference Tuesday. But how can the United States shape the local balance of power without intervening directly and without arming favored rebel factions? Apparently, according to Walt, it cannot, which means that offshore balancing is doing no better at advancing U.S. interests than on-shore involvement.

The failure of offshore balancing does not prove the wisdom of military intervention. Perhaps Syria and Afghanistan are hopeless cases and, if so, there is an argument for not squandering American resources in futile efforts.

But Walt's implicit critique of offshore balancing points the way to a fuller exploration of the strategy, one that would go well beyond this blogpost. If even academic proponents of offshore balancing mock its core components, is it any wonder that policymakers with real responsibility for results will be reluctant to rely on it alone?

Offshore balancing is no panacea, just as military intervention is no panacea. Yet when even proponents of offshore balancing denigrate the tools that the strategy requires, it may be time to rethink its basic premises. 

For months, the Obama administration has been avoiding the conclusion that the Assad government used chemical weapons in its armed struggle to suppress its citizens. As recently as yesterday, Defense Secretary Chuck Hagel rebuffed the notion, saying "suspicions are one thing; evidence is another." 

Today the White House finally conceded the point. "Our intelligence community does assess with varying degrees of confidence that the Syrian regime has used chemical weapons on a small scale in Syria, specifically the chemical agent Sarin," the administration wrote in a letter to Congress.

But even now, the White House is insisting it needs to gather the facts and called for a U.N. investigation, a convenient method of continuing to stall on Syria. 

The letter goes on to say that "given the stakes involved, and what we have learned from our own recent experience, intelligence assessments alone are not sufficient -- only credible and corroborated facts that provide us with some degree of certainty will guide our decision-making and strengthen our leadership of the international community." It endorses a "comprehensive United Nations investigation that can credibly evaluate the evidence and establish what took place." (The U.N. has already deployed a team to Cyprus to investigate allegations of chemical weapons use in Syria, but so far they have been denied entry into the country, and a full-throated investigation remains unlikely.)

The world's best intelligence services are generally acknowledged to include those of Israel, Britain, France, and the United States, yet for months we alone are unable to establish whether chemical weapons have been used in Syria. As technical assessments have traditionally been the strong suit of American intelligence, it is curious that we alone among the major intelligence assessors were unable to determine whether chemical weapons had been employed.

The governments of Britain and France informed the United Nations they have credible evidence that Syria has more than once used chemical weapons. They took soil samples from the suspect sites and subjected them to rigorous testing, interviewed witnesses of the attacks in Homs, Aleppo and Damascus, and became convinced nerve agents were used by the government of Syria.

"To the best of our professional understanding, the [Syrian] regime used lethal chemical weapons against gunmen in a series of incidents in recent months," General Itai Brun, chief of the research division of Israel's army intelligence branch, said Tuesday.

Even the government of Syria acknowledged that chemical weapons were used, though they unconvincingly claimed the chemical weapons were used by the rebels and refused entry to U.N. investigators.

Our European allies have said they believe the Syrian government "was testing the response of the United States." Until today, the response of the United States has been to avoid coming to a conclusion. 

General Brun made that public statement while Secretary of Defense Chuck Hagel was in Israel. Hagel's reaction? He claimed the Israeli government didn't share that information with him. But the Obama administration's secretary of defense didn't double back to get the information. He didn't strengthen deterrence by reiterating the president's "red line" that any chemical weapons use by the Assad government would bring U.S. retaliation. He expressed a complete lack of curiosity on the subject, saying "suspicions are one thing; evidence is another."

Hagel has now been forced to backtrack. "As I have said, the intelligence community has been assessing information for some time on this issue, and the decision to reach this conclusion was made in the past 24 hours," Hagel said, "and I have been in contact with senior officials in Washington today and most recently the last couple of hours on this issue." Hagel added that "we cannot confirm the origin of these weapons, but we do believe that any use of chemical weapons in Syria would very likely have originated with the Assad regime." Hagel's statement taken together with the "varying levels of confidence" modifier included in the White House's letter to Congress means that the Administration is still avoiding a conclusion; they will surely want an intelligence community consensus with a very high level of confidence (something rarely achieved).

Because if it should be "proven" that the Assad government has used chemical weapons, it will either force the president's hand to intervene in Syria, or the president will be revealed to have made threats he declines to back up. Instead, the administration has chosen to conclude that the intelligence is inconclusive.

It would be deeply inconvenient for the president of the United States to have to go to war in Syria when he placidly assures the American public that the tide of war is receding. U.S. intervention grows even more inconvenient since our unwillingness to help the rebels has led them to take help from quarters we disapprove of -- are we to fight alongside the al Nusra front, which we (rightly) characterize as a terrorist organization with al Qaeda links?

It is a problem of the president's own making, of course: He took a strident stand that any chemical weapons use would be a "game changer" precipitating American military involvement. This president likes to look tough on the international scene -- even when he's leading from behind he's taking all the credit. So we have policies designed to showcase Obama as a commanding commander in chief.  In order to keep him from having to make good on his threats, the administration has taken to relying on intelligence assessments as his opt-out. 

The Syria evasion is of a piece with Obama administration deflections of other intelligence conclusions that would force a change to their policies: Iran and North Korea.  

With regard to the Iranian nuclear program, President Obama gave a speech (at AIPAC, no less) insisting that he would not settle for containment of a nuclear-armed Iran; he would prevent it. Since then, the secretary of defense and the director for national intelligence have both testified to Congress their strong belief that Iran "has not decided to make a nuclear weapon." In so carefully parsing their language, they are attempting to remove from consideration the evidence of Iran's capability to build a nuclear weapon in order to assert as more important Iran's intent.

What neither the secdef (then Leon Panetta) nor the DNI acknowledged is that assessing intentions is the most difficult part of intelligence work and requires a supple and deep understanding of the politics of other governments -- something we are unlikely to have about a country with complex political dynamics unhindered by institutional constraints and in which we have not had a diplomatic or economic presence for 34 years.  

The Obama administration is unconcerned that other countries who have at least as good an intelligence operation directed at Iran as we do don't share our confidence that Iran hasn't made the decision to proceed. When challenged on the divergent assessments, now Secretary of Defense Hagel explained there might be "minor" differences between the U.S. and Israel on the timeline for Iran developing nuclear capacity. The Obama administration's generous timeline is a function of them "knowing" that Iran hasn't decided to proceed.

With regard to the North Korean nuclear test and military provocations, President Obama insisted he would not reward bad behavior (even as Secretary Kerry visiting Seoul offered negotiations). Lieutenant General Flynn, director of the defense intelligence agency, which is the arm of U.S. intelligence most focused on assessing military capabilities, testified before Congress that in DIA's judgment, North Korea already has the ability to mate nuclear warheads to long-range missiles. The administration's response?  The President denied the conclusion in a nationally-televised interview. The director of national intelligence, Jim Clapper, also gave interviews explaining that DIA's conclusions are "not the consensus view of the intelligence community."

This is what the politicization of intelligence looks like: politicians turning their eyes away from information that is inconvenient to their agenda. It's always a bad idea.

In his excellent critique of the critics of the Bush foreign policy legacy, Peter Feaver spotlighted Water Russell Mead's advice to Republicans to reflect "openly and honestly" on how the 43rd President forever corrupted the GOP's foreign policy credentials. Every time I hear this advice -- usually given by my Democratic friends in sorrow rather than anger -- I ask them when Democrats will reflect openly and honestly on how their own caricature of Bush foreign policy has distorted and crippled their party's capacity for strategic thought.

The fundamental flaw in President Obama's grand strategy lies in its origins -- a view of America's role in the world crafted as the mirror image of a self-satisfying political narrative about Bush. It was a worldview based on the projection of their critique of Bush onto the world and not on the fundamental dynamics of power and competition that actually exist in the international system. In the editorial pages of the New York Times, faculty lounges across the country, and the Phoenix Project on foreign policy in Washington, a hugely simplistic assessment of Bush foreign policy emerged between 2001 and 2008. American foreign policy, it was decided, had become unilateral and militaristic. Our standing in the world had collapsed (an assessment based on Western European polling and one that ignored repeated polls in Asia and Africa that showed the United States was considerably more popular at the end of the second Bush administration than the end of Clinton's time in the White House). We were not willing to talk to our adversaries, etc.,etc. 

As a result, the Obama foreign policy doctrine that emerged was entirely process-oriented and based on each of these critiques. How could the United States stabilize relations with China? By cooperating on climate change, a supposedly win-win transnational theme neglected by Bush. How would the administration solve the dangerously revisionist policies of Iran and other members of the Axis of Evil? Through engagement and dialogue, an obvious tool not exploited by Bush. How would the problems of proliferation be addressed? Through a visionary speech in Prague on total nuclear disarmament, something anathema to Bush. How to handle human rights and democracy? Smarter to tone down naming and blaming so that we could reassure countries like China and Iran that we were no longer pursuing a dangerous neocon policy.

In bits and pieces realism and realists emerged triumphant in the first Obama term. Hillary Clinton's Asia policy stands out, as does the triumph of realists in the debate over the Nuclear Posture Review. But what is the Democratic foreign policy establishment's basic doctrine today? Absent the organizing principle that Bush was the root of our problems, there is no core doctrine. Of course, the critics said Bush had a doctrine ... so maybe it would be better not to have one of those after all.

This week, the George W. Bush Presidential Center will be dedicated. It will be a fun reunion of people who served in the Bush administration -- those who helped advise, make, and implement the president's policies in a time of great consequence for American history. 

The opening of the presidential library has coincided with dramatic events at home and abroad that have eerie echoes to the Bush-era -- a Boston terror attack that reminds people of the post-9/11 jitters, ricin-laced letters to politicians that remind people of similar anthrax attacks, and an unraveling sectarian civil war in the heart of the Middle East, complete with intelligence reports of WMD use, that reminds people of the bitter experience in Iraq. 

All of these have occasioned a great deal of talk about the Bush era and renewed debate about the Bush legacy. The talk and debate is welcome, but sometimes it takes a curious turn.

Case in point: consider Walter Russell Mead's two posts about the Bush legacy, the first of which Will Inboden rebutted last week. 

Let me begin by emphasizing that I have a lot of respect for Mead. I assign some of his books to my students, I find his blog posts to be usually thoughtful, and I appreciate that he is not a predictable Johnny-one-note on foreign policy.

Yet, on balance, his contribution to the current wave of commentary on the Bush legacy seems to be more an example of what not to do than of what to do. He opened with a provocative post entitled "The GOP Needs to Talk About Bush: Part One," in which he claimed that Republicans need to, well, talk about Bush "openly and honestly."

In his follow-up "part two" post Mead mocked Peter Wehner for, well, talking about Bush openly and honestly. 

Mead's rebuttal to Wehner consisted of two pillars:

First: claiming (falsely) that Wehner's argument was premised on the belief that Bush had done nothing wrong and that all bad things that happened on Bush's watch should be entirely blamed on others. But Wehner explicitly acknowledged important mistakes and he explicitly called for shared responsibility. Apparently, Mead saw no middle ground -- no via media, if you will -- between a claim on the one hand that all critiques of the Bush presidency are true and a reductio ad absurdum claim on the other that the Bush presidency was a "triumph, a sterling example of greatness, of competent benevolence mixed with wisdom almost divine..." Instead of productively exploring the middle ground, Mead derisively dismisses a caricatured version of Wehner, one entirely of Mead's fabrication. 

Second: passionately arguing that any attempt to answer critiques of the Bush era plays into the hands of the Bush-haters and is backward-looking. Never mind that this Pillar directly and obviously contradicts Mead's first post, which, as you will recall, encouraged everyone to talk "openly and honestly" about the Bush era (i.e. to look backward with clear eyes so as to move forward). The only possible way to reconcile them is to believe that what Mead meant in his first post is something like this: "Republicans should embrace every criticism of Bush, no matter how wrong or illogical because to answer such criticisms is to play in the hands of the Bush-haters." Why would accepting bogus critiques of the past prepare us well to face the future?

What is curiously missing in Mead's response is any factual or logical engagement of Wehner's (or Inboden's, for that matter) actual argument. Perhaps Wehner or Inboden have over-claimed or misread the history. If so, I would like to see the facts and logic that make up that case. 

I wonder if there are two Walter Russell Meads (that would explain why the Via Media refers to itself with the first person plural). There is the Mead who has written important books that are must-reads for any student of American foreign policy and who has offered thoughtful commentary on an impressively wide range of topics. That same Mead, in his "Part One," acknowledged that many Bush-haters distort the past in their critique. And then there is a second Mead, the one who trashed Wehner for engaging in the historical conversation Mead #1 claimed to want. If so, I hope Mead #1 will start debating Mead #2.

Of course, the problem is not really Mead, who, I would argue, will eventually be part of the solution. Compared to other pundits back in the day, he had something of a balanced view of the Bush administration as it unfolded. In fact, I would turn the frame upside down: if reasoned, fact-based discussions of the Bush Legacy cannot produce balanced and nuanced assessments from generally fair-minded observers like Mead, then I would despair of ever seeing it at all. 

Happily, the truth is that, over time, we can see such appraisals emerging. Some scholars not blinkered by ideological opposition do produce more balanced assessments than what the conventional wisdom of the day, which is still overly shaped by the instant partisan commentary, would predict. Thus, Mel Leffler has a balanced account of the origins of the Iraq war, Stephen Biddle and his co-authors have a sophisticated analysis of the contributions of the Iraq surge, and Robert Jervis has a careful review of the intersection of intelligence failure and policy choice in Iraq. 

None of these scholars can be dismissed as court sycophants. All would, on balance, come down more negatively on the Bush legacy as a whole than the typical Shadow Government contributor. Yet, like the typical Shadow Government contributor, each seems committed to letting the facts lead where they may, even if those facts will disrupt the settled caricatures of the conventional wisdom.

Some journalists are coming around, too. Ron Fournier has a thoughtful commentary that humanizes former President Bush. And maybe even the public is showing an openness to reconsidering previous opinions.

Therefore, I think Republicans should be willing to talk openly and honestly about the Bush era. That will involve accepting some critiques but rejecting others. That will require conceding some mistakes and explaining why the conventional wisdom is wrong in other respects. I do not think that should be the sole or principal preoccupation of Republicans, nor do I think we are in any danger of Republicans falling into that trap. 

A worthy contribution of the new Bush center to the ongoing political dialogue in the country would be if it used its convening powers to conduct careful and detailed explorations of key decisions and policies from the Bush era. With the benefit of hindsight, such explorations may conclude that some decisions and policies were mistaken and, if so, the center can be candid in acknowledging that. 

Yet I am confident that such a rigorous analysis of the past will produce a more balanced assessment than the conventional wisdom holds. And I am confident that such rigor and balance will be more useful to Republicans going forward than caricature is.

The failure of the latest round of negotiations over Iran's nuclear program will likely bring calls for changes in the American approach -- for bilateral engagement, for an "endgame proposal," or even for reconsideration of the merits of "containment" of a nuclear-weapons-capable Iran. One such proposal -- focusing on strengthening the US "diplomatic track" with Iran -- was put forward recently by The Iran Project, a group of distinguished former U.S. officials.

There is much in the report with which I agree. In particular, the report is correct to observe that neither sanctions nor engagement alone will accomplish U.S. aims and that a combination of policy tools will be required. It is also right to begin with an assessment of U.S. and Iranian interests and objectives, which should be the starting point for any successful policy.    

However, I would differ with the report on four vital issues and thus reach different conclusions regarding the way forward on Iran policy.

First, the report conflates the objectives and interests of Iran writ large with those of the Iranian regime. The principal-agent problem that bedevils even democratic governments is particularly pronounced in authoritarian regimes, such as Iran's, which are not accountable to an electorate. Care must therefore be taken to distinguish between Iranian national interests and regime interests.

When it comes to sanctions, the Iran Project report's own conclusions illustrate this distinction -- the economic costs imposed upon Iran have certainly set back Iran's national interests but have had little apparent impact on the regime's own calculus, likely in part because Iran's leaders are relatively sheltered from the impact of sanctions compared to ordinary Iranians.

This distinction must also, however, be applied when designing incentives. What the report lists as Iranian aims -- respect, acknowledgement of nuclear "rights," etc. -- appears based on the rhetoric of regime officials. That rhetoric has multiple audiences in mind -- especially public opinion in Iran and the Middle East -- and therefore deliberately obscures the gap between the interests of the regime and those audiences. An examination of Iran's policies and actions, on the other hand, suggests that the regime is primarily interested in the enrichment of regime elites, the projection of power throughout the region to ward off potential foes, and especially in the survival of its "velayat e-faqih" system of rule.

Second, the report draws a false distinction between "diplomacy" and "pressure." There is a widespread misconception that diplomacy means "being nice," which leads to engagement being seen as a reward. In fact, diplomacy is just the conduct of relations between states -- a means of communication. A skilled diplomat will use these communications both to pressure and to entice, as well as to learn about his counterpart. Whether any particular action constitutes a disincentive or incentive depends on whether it damages or advances the Iranian regime's interests, which is why understanding how the regime truly views its interests is critical to diplomatic success.

Third, the report treats Iran's nuclear ambitions as the result of U.S.-Iran hostility. In reality, both likely arise from the regime's desire to preserve itself. Anti-Americanism was a founding pillar of the current Iranian government, and abandoning it would undermine the regime's raison d'etre. As for nuclear weapons, they would under the right conditions provide Iran with a powerful deterrent to external attack. Furthermore, the regime may calculate -- based on U.S. policy toward North Korea during its recent leadership transition, as well as U.S. policy toward Pakistan -- that fears of "loose nukes" would cause outside powers not simply to be deterred, but give them a vested interest in the regime's stability. Because the threats to that stability emanate from within as well as without, Western security guarantees are unlikely to be regarded as an acceptable substitute for a nuclear arsenal.

Fourth, and most problematically, the report assumes that a nuclear agreement could result in a broader strategic shift by Iran. In fact, a nuclear agreement -- and any improvement in U.S.-Iran relations -- is more likely to be a consequence of such a shift than a cause of one. As noted above, both Iran's nuclear ambitions and its hostility toward the West are elements of a strategy to advance the regime's interests, as it conceives them. For a strategic shift to occur, the regime must be convinced that this strategy is no longer tenable.

Far from compelling the regime to rethink its strategy, however, the current Western approach is likely seen in Tehran as vindicating it. U.S. policies at the negotiating table and across the region -- a reduction in our military posture, our inaction in Syria, and our continually improving nuclear offers -- are interpreted as successes by the regime and perceived by it as indications not of good will but of desperation or decline. 

Seen in this light, rather than forcing the regime to face a stark choice, the U.S. and our allies have given Iran's leaders the impression that they can have their cake and eat it too: retain an implicitly acknowledged nuclear weapons capability and not only maintain but expand its regional influence without having to adopt a posture of international cooperation.   

The U.S. objective, therefore, should be to reverse this dynamic. Such an approach would require a firmer posture in the nuclear arena -- refraining from further improvements to our offer, setting red lines for Iran's nuclear program, taking  steps to enhance the credibility of the U.S. military threat, and leaving open for now the question of whether we will hold further talks. 

But it would also require putting the nuclear negotiations in their appropriate regional and strategic context. The regime should come to believe that a confrontational, rather than cooperative, approach to its own security will come at a price, exacted by the U.S. and our allies. There are a number of ways to send this message -- pushing back against Iranian support for terrorism, greater support for the Iranian opposition -- but the most important way to do so is through greater involvement in Syria, where Iran has much at stake.

None of these steps exclude continued or even intensified diplomacy. Successful policies should combine a range of tools employed in coordination. But the goal of all of these actions should be the same. A strategic shift by Iran -- from a zero-sum policy of confrontation to one of cooperation -- would benefit the U.S. and the region whether or not a formal nuclear agreement is reached. A nuclear agreement without such a shift, however, will prove a hollow achievement.

The policy world has turned on Ken Rogoff and Carmen Reinhart with a vengeance. The two are the celebrated authors of multiple studies showing that very high levels of government debt have historically been associated with slower growth. After a review of one of their articles revealed a spreadsheet mistake, the ever-temperate Paul Krugman was driven to ask: "Did an Excel coding error destroy the economies of the Western world?"

John Maynard Keynes once said that "even the most practical man of affairs is usually in the thrall of the ideas of some long-dead economist."Apparently, this bondage is felt even more acutely when those practical men are in the thrall of a living, breathing pair of economists. Now that Rogoff and Reinhart have been discredited, the thinking seems to go, the masses who had been suffering under the yoke of austerity are now free to spend as they had always wished.

There are a number of reasons to see this as an overreaction. The episode is a bit analogous to a researcher finding that a daily Twinkie adds 10 pounds over a year. A subsequent study finds that, with different methodology, a daily Twinkie might add only 5 pounds over a year. Then the baying pack howls that they knew Twinkies were good for you all along, they abjure dieting, and stuff themselves with cake and cream filling. [Reinhart and Rogoff respond to the criticisms and put the dispute in the context of a broader literature without resorting to any talk of dessert cakes.]

An odd strain of the discussion has been the implication that the only restraint on unbounded budget deficits has been the Reinhart-Rogoff admonition that it could slow economic growth. In fact, there are other constraints. How much can Portugal or Greece or Cyprus spend beyond current tax revenue? They can spend the money they have in savings (negligible) plus the amount they can borrow in the open market (negligible) plus the amount that other countries or international financial institutions (IMF, ECB) are willing to lend them. The limitation, then, is not Harvard researchers' findings but rather the willingness of other leaders to risk their funds, as their thoughts teem with admonitions about "sending good money after bad."

Of course, countries such as the United States, France, or the UK can borrow on open markets. That does not free them from all non-academic constraints, however. If borrowing is excessive, a country begins to look riskier. The United States was downgraded in 2011, France in 2012, and the UK last week. Even the IMF, cheering now for a spending boost, has argued for offsetting medium-run budget cuts.

The Reinhart-Rogoff episode has prompted deeper ruminations about how grounded our economic beliefs really are. In the Wall Street Journal, Carl Bialik elicits a confession from the editor of the American Economic Review that peer review rarely involves line-by-line checks of authors' calculations. Bialik lays bare some of the inherent vagaries of working with historical macroeconomic data -- there are no controlled experiments and the numbers can be unreliable.

It is thoroughly healthy to review the limitations of empirical macroeconomics. It is the part of economics that deals with the most moving parts and has the least opportunity to isolate treatment effects from confounding variables. Economics does far better as a field when conditions are more favorable -- predicting how an auction will work, for example. Yet citizens and policymakers want to know what will happen with inflation, unemployment, and growth, and how these will be affected by government spending, taxes, and the money supply. These are all macroeconomic questions.

Let's stipulate, then, that macroeconomic point estimates should be treated as somewhat fuzzy. That was always acknowledged in the formal economics (standard errors), but it does not usually make for good newspaper copy. If multiple studies, using different data sources and different techniques, find similar results, then we will have steadily more confidence in those findings. This has always been true too, though in public debate participants tend to prefer a single bold study to a lengthy lit review.

The newfound caution about macroeconomic findings has, so far, been curiously selective. Foes of austerity argue that, after slaying the dreaded Reinhart-Rogoff result, they are not even bound by warnings of credit downgrades. After all, if only we adopt new fiscal stimulus, it will promote growth and pay for itself (debt/GDP will fall as GDP rises faster than debt).

How do we know this? Why should we believe that the stimulative effects of new spending will overcome people's worries about the new taxes that will inevitably follow? How can we calculate how much stimulus is appropriate? Are tax cuts or spending increases more appropriate? If we do not see booming economic growth after stimulus has been tried, how will we know that the stimulus was worthwhile, that it saved us from an even worse fate?

We have macroeconomic findings. Precisely calculated macroeconomic findings. Based on historical data. Published in peer-reviewed journals. Worked out on spreadsheets. Let the spending commence.

While America's attention has been drawn to last week's terrorist attack upon Boston, events in North Korea continue to be cause for concern. The revelation last month that North Korea has taken "initial steps" to deploy a mobile intercontinental ballistic missile, the KN-08, and the disclosure earlier this month that at least part of the U.S. intelligence community believes "with moderate confidence" (in intel-speak) that it possesses the ability to deploy a nuclear warhead atop the missile highlight the threat that Pyongyang poses to the United States. 

It should come as no surprise that North Korea possesses, or will soon possess, the ability to strike the United States with a nuclear-armed ballistic missile. After all, U.S. government commissions, U.S. and foreign intelligence agencies, and defense analysts have been warning of this eventuality for more than a decade. Pyongyang has been working on nuclear warheads for two decades and has conducted three nuclear tests. Both Israel and South Africa, by contrast, developed nuclear warheads for their missiles without conducting any nuclear tests. Moreover, as Peter Pry noted last week, the United States has possessed for more than fifty years nuclear missile warheads smaller and lighter than the satellite that North Korea lofted in December. 

Skeptics will argue that North Korea has yet to demonstrate it has the ability to deploy nuclear warheads atop its ballistic missiles. Fair enough. But policy makers should not have to wait for Pyongyang to test a nuclear-armed ICBM to respond -- particularly when countermeasures are likely to take years to come to fruition.

The very real threat posed by North Korea has thrown into sharp relief the Obama administration's zig-zagging on missile defense. After coming to office, Obama's team scrapped the Bush administration's missile defense plan, putting in place the Phased Adaptive Approach that promised to deliver more effective missile defense based upon yet-to-be developed interceptors such as the Standard Missile 3 IIB. 

Some analysts suspected at the time that the Obama administration was engaging in a game of bait-and-switch, junking a missile defense system based upon proven technologies in favor of a supposedly better one down the line that it would then fail to fund. It thus came as something less than a surprise when, in a move largely missed by the major news outlets, last month Secretary of Defense Hagel announced the cancellation of the final phase of the missile defense plan while promising to beef up the Bush-era missile defense site at Fort Greely, Alaska. These interceptors will not be deployed until 2017, however. 

Enhancing U.S. missile defenses in response to North Korea's nuclear missile program would appear to be warranted, but it alone is likely to prove insufficient.  The United States should consider enhancing its ability to strike North Korea, including its leadership and its ballistic missile launch infrastructure. As former Secretary of Defense William Perry and current Deputy Secretary of Defense Ashton Carter wrote on June 22, 2006:

"Should the United States allow a country openly hostile to it and armed with nuclear weapons to perfect an intercontinental ballistic missile capable of delivering nuclear weapons to U.S. soil? We believe not."

Perry and Carter went on to argue in favor of a pre-emptive strike on a North Korean test missile on the launch pad. It would be worth asking Carter whether he continues to hold this view.

Finally, the United States should explore ways to enhance its extended nuclear deterrent of its allies, particularly South Korea and Japan. The Obama administration's 2010 Nuclear Posture Review scrapped the nuclear variant of the Tomahawk missile, which Tokyo looked to as the embodiment of the U.S. nuclear guarantee, and yet is years away from fielding the variant of the F-35 strike aircraft that will be capable of carrying nuclear weapons. Reassuring U.S. allies in the face of North Korean nuclear threats is likely to be both vital to stability in the region and an increasingly challenging task.