James Mann, who is the author of a number of books on foreign affairs, has a thoughtful essay in Sunday's Washington Post about Robert Kagan's new book The World America Made (which National Interest editor Robert Merry also critiqued a few weeks ago on this site). The title affixed to Mann's piece suggested that Kagan might even be President Obama's "guru"—something that Mann actually does not say. Kagan's contention is that the rising belief in the decline of America is bunk. Far from being headed for the skids, America has been here before and recovered.

Kagan's book has caused something of a stir. Not just because Kagan is good at stirring up controversy (though he is) but also because President Obama has apparently bestowed his benison upon the book. In his most recent State of the Union address, Obama said that the notion, propagated mostly on the right, that America is a declining power is not true. Obama has also apparently closely read the New Republic essay that excerpted Kagan's book and recommended it to the folks that work on his national-security council staff. The idea that Kagan, who is a top adviser to former Gov. Mitt Romney, might be a national-security adviser in a Romney administration has caused some discombobulation in Washington. How can this be? some folks are wondering.

Mann has a compelling answer. Kagan is not a partisan. Instead, he's interested in ideas. The main idea that he's interested in is a simple but powerful one—that America is, by and large, a force for good in the world. If it goes AWOL, then democracy, liberalism and the other good things that America stands for would take a pasting around the globe. Kagan is probably closer to the older Democratic Truman-Acheson tradition than he is to any Republican foreign-policy traditions. Mann observes,

Although “The World America Made” has attracted considerable attention for debunking the idea of American decline, this critique is merely one part of Kagan’s larger argument — one that should prove even more controversial on both the left and the right, once fully grasped: He maintains that the United States should continue to serve as the world’s benign hegemon, its global cop.

It's nice to practice hegemony, as long as the costs are bearable. But are they? For all his rhetorical embrace of America vigor, Obama is not exactly following Kagan's program. He has been tepid about the Arab Spring. He "led from behind" in Libya. He's stalling on intervention in Syria. He's pulled American troops out of Iraq—too precipitously, argue some neocons. And he may be forced to accelerate America's retreat—let's be honest about the wording—from Afghanistan.

So it could be argued that Obama is something of a Machiavellian, at least when it comes to appropriating Kagan's message. He's trumpeting American reneweal even as it tries to hand off more responsiblities to its allies. All along, Obama's strategy has been to drape himself in the national-security rhetoric that the GOP has employed for decades. Obama is presenting himself, the slayer of Osama bin-Laden, as Mr. Big when it comes to dealing with the rest of the globe. And, to some extent, he's succeeding. Polls suggest that the American public does not see Obama as some kind of liberal wussbag. Quite the contrary.

The broader point to be derived from Kagan's stimulating book is probably that the terms of debate are not really as capacious as the GOP would make out. There is substantial agreement that an American retreat from the world would be disastrous and that power matters. The extent to which America's relative advantages are eroding, however, is fertile ground for debate and will become increasingly apparent in the coming decade, no matter who's president.

Image: Mariusz Kubik