Barack Obama is not the man many Americans thought he was. This sudden realization has transformed American politics.

The sheer audacity of the successful operation against Osama bin Laden has forced Obama’s friends and foes alike to reassess what they make of a chief executive who defies easy categorization and reveals less about himself than politicians are typically drawn to do.

Obama is hard to understand because he is many things and not just one thing. He has now proved that he can be bold at an operational level, even as he remains cautious at a philosophical level. His proclivity to gather facts and weigh alternatives does not lead automatically, in the venerable phrase, to the paralysis of analysis. It can also end in daring action tempered by prudence — for example, making sure that additional helicopters were available to our Navy SEALs.

The president’s rhetoric has often emphasized caring, compassion and community, the language one expects from a moderately liberal politician. Yet as one of his close aides told me long ago, there is inside a very cool, tough, even hard man. Obama is not reluctant to use American military power. He was not at all queasy about authorizing the killing of an American enemy and the disposal of the body at sea to ensure that there would be no memorial to rally bin Laden’s followers.

Obama told us who he is in one of the most celebrated statements he made — about the war in Iraq — before he ran for president. His listeners tended to pay far more attention to the war he criticized than to his reasons for criticizing it. “I am not opposed to all wars,” he declared in 2002. “I’m opposed to dumb wars.” Note when it comes to armed conflict, the word “dumb” is not typically part of the lexicon of a moralist.

The fact that Obama is not a moralist has led to many of the frustrations vented about him over the past 27 months. Liberals don’t get why it takes him so long to get around to taking on the political right over the fundamental purposes of government and the requirements of social justice. Advocates of democracy and human rights ask why he was so slow to invoke the word “democracy” as a touchstone of his foreign policy, and why he was so guarded in his initial response to the Arab Spring.

Supporters of a muscular and interventionist American foreign policy suspect him of believing that the decline of the United States is unavoidable and of seeing himself primarily as a steward whose task is to manage our steady loss of influence.

It is this last claim that took such a profound blow when Obama approved the operation against bin Laden and chose the riskiest option involving a face-to-face confrontation with American commandos — on the orders of the president of the United States.

Obama’s conceptual complexity means that he rejects the idea that there are just two alternatives: the United States as the world’s sole superpower or an America slinking off into weakness and irrelevance. Binary choices are not for him.

Instead, he sees a world in which new powers — China most obviously, but also India and, someday, Brazil — inevitably rise to challenge American dominance. The United States’ task is not to prevent the ineluctable emergence of other strong nations. Its imperative is to remain an enormously powerful force fully capable of shaping the globe’s new arrangements, defending its interests and values, and prospering in an ever more competitive environment.

And anyone who doubted our willingness to project our might as we see fit will have second thoughts after the events in Abbottabad.

This single action does not “change everything,” because nothing ever changes everything. Killing one man does not settle two messy wars. Obama’s political standing will ultimately rise or fall largely on the basis of domestic issues and economic circumstances. The president’s supporters will again experience bouts of frustration when his philosophical caution prevails over his bold streak in the less martial work of negotiating budgets and promoting the general welfare at home. His opponents will not suddenly embrace his priorities.

But because he ordered this attack, and because it was successful, no one will ever view Barack Obama in quite the same way again.

ejdionne@washpost.com