Defense Secretary Robert Gates capped off his visit to Duke Wednesday with a remarkable speech. It underscored once again why most people, me included, think he is President Obama's most inspired cabinet pick and most capable member of the national security team.

Full disclosure: Secretary Gates came to Duke, my place of employment, as part of my program on American Grand Strategy, to give the Ambassador S. Davis Phillips Family International Lecture, which I help plan. He even came and taught a session of the American Grand Strategy class I teach with Prof. Brands, a diplomatic historian (I am the guy with the bad haircut pointing a finger in the photo here). So if he had given eight minutes long garden-club remarks I would have found a way to be happy.

But he didn't. He gave a thoughtful and substantive speech on a topic near-and-dear to my heart: the special challenges of an All Volunteer Force (AVF) in an age of prolonged war. Watch the speech for yourself and I think you will see why I was so impressed (and why I was reliably informed that I need a haircut).

After a brief joke about college football (which riled the crowd given Duke's recent loss to Army), Secretary Gates began by noting the parallels between being responsible for young people as a college president and being responsible for young people as secretary of Defense. This responsibility is all the more daunting because we are fighting our longest war in history with our smallest military -- or as Gates put it, "no major war in our history has been fought with a smaller percentage of this country's citizens in uniform full-time."

Although he supported the AVF and rejected the draft as a viable alternative, his speech focused on three adverse consequences:

1. Portions of the military, especially the ground forces, are experiencing acute stress with repeated deployments. The strain on the force is evident in rising suicides, other PTSD-related health issues, and familial problems. Gates asked a poignant rhetorical question that I hope will trigger a national conversation: "How long can these brave and broad young shoulders carry the burden that we -- as a military, as a government, as a society -- continue to place on them?"
2. The financial costs of the AVF may be reaching the breaking point. It is not just the pay and benefits of the active force. Even more challenging are the costs of the retiree force -- costs that will grow for decades to come. Gates mentioned delicately the politically fraught nature of this issue, and emphasized the importance of caring adequately for those who have served our country at such great risk to themselves. But he also noted some uncomfortable truths that could spark a national debate on their own, such as: "The health care component has grown even faster, from $19 billion a decade ago to more than $50 billion this year, a portion of that total going to working-age retirees whose premiums and co-pays have not been increased in some 15 years. "
3. Exacerbating a "gap" between the part of U.S. society with close ties to the military and the vast majority with none. He was really preaching to the choir at this point. This has been a matter of considerable study for one of his local hosts, the Triangle Institute for Security Studies. The entrepreneur in me heard a clarion call for a follow-on study looking at the gap question in light of a decade of war.

But perhaps the most surprising part of the speech was the very end when he made an explicit appeal for Duke students to consider joining the military. It deserves to be quoted at length:

So I would encourage you and all young Americans, especially those at the most selective universities who may not have considered the military, to do so. To go outside your comfort zone and take a risk in every sense of the word. To expand what you thought you were capable of doing when it comes to leadership, responsibility, agility, selflessness, and above all, courage.

For those for whom military service is neither possible nor the right thing for whatever reason, please consider how you can give back to the country that has given us all so much. Think about what you can do to earn your freedom -- freedom paid for by those whose names are on that Duke wall and in veterans' cemeteries across this country and across the world.

He noted the sacrifices and risks, calling attention to two Duke alumni "who made the ultimate sacrifice in Iraq. Matthew Lynch, class of 2001, champion swimmer, following in his father's footsteps as a United States Marine. And, James Regan, class of 2002, son of an investment banker who turned down offers from a financial services firm and a law firm to join the army rangers."

But still he urged the Duke students -- and the many students in the audience from UNC-Chapel Hill, North Carolina State University, and North Carolina Central University -- to join the fight. This may seem like boilerplate, but to this audience it was anything but. It was surprising and moving and provoking -- provoking thought and perhaps even action.

Gates made news at Duke. But of greater consequence, he made a large audience of young people think about important things that are all-too-easy to ignore.