On a sweltering Washington sidewalk on July 17, a handful of protesters berated the stream of bespectacled wonks entering the “stink tank” known as the American Enterprise Institute (AEI) — famous worldwide as the home of former Pentagon official Richard Perle and former House Speaker Newt Gingrich. In the air-conditioned comfort inside, the lusty strains of “Rule Britannia” welcomed a capacity crowd to AEI’s version of a summertime idyll. We were assembled to hear two vaunted thinkers of the new, new world order debate the proposition that America is, and should be, an empire.

As recently as two years ago, describing the United States as an empire defined one as a Marxist. No longer. British imperial historian Niall Ferguson and neo-conservative guru Robert Kagan did not debate the proposition so much as quibble over the meaning of words. Both promoted an image of the US as a benevolent superpower with one discernible interest — to render the world safe for democracy and free enterprise. This interest, the debaters agreed, was noble, even altruistic.

But despite its virtue, posited Ferguson, the United States was an “empire in denial.” Because Americans stubbornly refused to acknowledge their global dominion, the US did not act as an imperium should. It dispatched Marines to troubled tropical climes on the false premise that, once they disciplined the unruly natives, they would be home in time to carve the Thanksgiving turkey. The US practiced “Wal-Mart” expansionism, consistently spending a fraction of what was required to pacify conquered countries. Finally, it relied too heavily on military coercion, failing to secure the collaboration of vassal states that made empires last. In the era of suitcase-sized nukes and Osama bin Laden, such a “colossus with attention-deficit disorder” was a danger to itself and others. The US should come to terms with its supremacy, and rule the world more responsibly.

Not exactly, Kagan rejoined. The US was not a fumbling empire in denial, in fact not an empire at all, but merely the most successful “global hegemon” in history. After Ferguson’s Oxonian verbal rigor, Kagan’s reasoning seemed flaccid. The US, he asserted, could not be an empire because it had no stated imperial design. (Didn’t Britain also acquire its domain “in a fit of absentmindedness?”) Americans had neither an imperial hymn like “Rule Britannia” nor an imperial poet like Rudyard Kipling. Contrary to popular belief, the US became less imperialistic in the late nineteenth and twentieth centuries — an implicit admission that manifest destiny was a doctrine of empire building. The ideology of American dominion subsided as American power grew. That, Kagan insisted, was the source of everyone’s confusion.

Much to the audience’s enjoyment, Kagan and Ferguson sparred further over terminology. “You don’t call another country the ‘evil empire’ if you don’t secretly believe that you are the ‘good empire,’” said Ferguson impishly. For now in Washington such debates are merely “great fun,” in the words of one departing spectator. But the intellectual jousting betrayed a growing, mostly unspoken consensus in the capital: American imperium is no longer a normative question, much less an empirical one. The answers now seem clear: Why fight wars to safeguard America’s sole superpower status in the future? Because that is the proper order of things. Why launch a crusade to “democratize” the authoritarian Arab world? Because we can.

This consensus belies what Kagan called the “myth of (America’s) Edenic innocence,” to which some on the left, and the traditional right, cling. The US has long been an empire afraid to speak its name. As Ferguson noted, the steady transfer of funds and foreign policy functions to the Pentagon is a classic sign of a republic losing its republican identity. What is left is for Americans, who like to consider themselves anti-colonial pioneers, to learn to love empire. First, the word must lose its pejorative connotations.

A cultural historian might argue that the very occurrence of the AEI event, together with the volumes about empire filling American bookstores, demonstrates that this process is well underway. Ostensibly neutral in the debate, AEI seemed to tip its hand by concluding the proceedings with music from “The Empire Strikes Back.” And in fact the speakers’ dispute over the term “imperial” reached its denouement when they concurred that Lenin and British historian John Hobson had ruined a perfectly good concept by attaching the suffix “ism” to it.

Nor did the hosts’ open minds embrace substantive dissent. Shortly before the debate began, AEI staff summoned police to expel two presumed infiltrators from the ranks of the protesters outside. Defending the action, an AEI spokeswoman told the Washington Post that the protesters were responsible for an overflowed toilet in the “stink tank” suite. As the blue-uniformed centurion removed one protester from the room, she appealed to the crowd to protect her free speech from this preemptive strike. No one said a word.