If elected, Barack Obama might make history in more ways than one. He will be the country's first black president, but also -- perhaps as consequentially -- could be its first transnational president.

Obama's personal history defies categorization, which makes it so alluring. Born in Hawaii to a black Kenyan father and white Kansan mother and raised for a time in Indonesia, Obama embodies the crosscurrents of globalization and the remarkable dynamism of an American society open to people of talent from any background.

Obama tells his story to emphasize its quintessential American-ness, a tale of how an outsider -- like so many before him -- came to live the American dream. This is all to the good. But at times it's a post-nationalism that comes to the fore.

His overseas tour -- punctuated by his Berlin speech before 200,000 -- showed him to be a potentially powerful American emissary to the world. It also suggested that Obama styles himself the world's emissary to us -- a discomfiting role for a would-be American president.

In Berlin, Obama called himself, unironically, a "citizen of the world." The world, however, issues no passports, nor does it have citizens. The world in the way Citizen Obama imagines it -- as a global community to which we all belong -- doesn't exist. Only backpacking hippies, devotees of the Davos World Economic Forum and U.N. bureaucrats speak this way.

Berlin at times sounded as much like Obama's coming-out party as the candidate of a transnational progressivism -- in which global norms are more important than sovereign nations -- as his audition as commander in chief.

In Obama's telling, a triumph of American arms and will during the Cold War was transmuted into a victory of a united world. He railed against "walls" of all kinds, even though walls are useful in dividing hostile communities (see, most recently, Israel and Iraq) and, in the form of borders, are the most basic stuff of nationhood. He addressed "people of the world" and told them "this is our moment, this is our time," as if the impossibly disparate people of the world can ever have a common will. Continued...