Using bold rhetoric that often makes his followers rapturous, Barack Obama has declared over and over that he will be the president of "change." But is Obama brave enough to bring about a really radical change? Will he end the permanent "war" George W. Bush has left us with? Will a candidate or a President Obama be willing to go so far as to question whether "the war on terror"—the framework for nearly every discussion of U.S. foreign policy today—is truly the pre-eminent challenge of our time?

Obama has come close. He has repeatedly called the war in Iraq a needless distraction, and he has accused Bush of "lumping" all sorts of enemies together. "It is time to turn the page," Obama declared last August in a defining speech at the Woodrow Wilson Center in Washington. "When I am president, we will wage the war that has to be won." But Obama's rhetoric still suggests that he too will be spending his term as a war president. And his "comprehensive strategy" for that war, while it calls for "getting out of Iraq and onto the right battlefield in Afghanistan and Pakistan," still implies that the Illinois senator believes the war on terror should be the overarching framework for his foreign policy.

Let's think about this for a moment. A small group of ragged America-haters, who had one lucky day of mass murder nearly seven years ago, will continue to define the foreign policy of the lone superpower for years, possibly decades to come. There's something wrong with this picture. Yes, we can all agree that 9/11 was one of the worst moments in American history. And we can certainly agree that Al Qaeda must be completely eliminated. But the group has never come close to duplicating 9/11; even the train bombings in London and Madrid that were attributed to Al Qaeda-inspired cells were minor by comparison. Are Al Qaeda and its ilk still really our number one challenge? What about global warming? What about the emergence of China, the resurrection of Russia, the decline of the dollar, the slackening of free trade, the spread of debt and disease, and the persistence of ethnic cleansing? What about the virus of "ethnonationalism," as Catholic University scholar Jerry Muller calls it in one of those big, defining lead articles—titled "The Clash of Peoples"—in the latest edition of Foreign Affairs? As Muller writes, the often violent dissolution of artificially constructed nations into ethnic subgroups is continuing in Europe and other places, especially Africa. Just this week the province of Kosovo unilaterally declared independence, provoking renewed violence by Serbs. Kosovo's move inspired one Palestinian negotiator to declare that maybe that wouldn't be such a bad idea for his people, either.

Bush said this week that he supports independence for Kosovo. But the back story is that for a decade since the Kosovo war the U.S. government has sought to avoid this outcome for fear that it would lead other ethnic subgroups in other countries to do the same thing. Indeed, some of America's knottiest foreign-policy problems involve the threat of "a state too far"—the unilateral declaration of independence in places such as Taiwan, Tibet, the Palestinian territories, Kosovo, Chechnya, and among the Kurds in Turkey and northern Iraq. In each of these cases Washington, in order to prevent conflict, is actively seeking to avert a declaration of independence (Taiwan, Tibet and the Kurds), is trying to avoid the issue altogether (Chechnya), or has been covertly blocking attempts to make it happen too soon (Palestine). And in the global echo chamber we are finding that these movements tend to study and cite each other as precedents. And they often invoke Woodrow Wilson's promises of "self-determination" after World War I, meaning that in some ways one of our main problems in the 21st century will be to deal with the implications of our own American ideas. One of the crowning ironies for U.S. policymakers today is that the right we asserted so eloquently for ourselves in the opening words of the Declaration of Independence—the right of a people to "dissolve the political bands which have connected them with another"—is, in practice, no longer something we recognize for other peoples.

None of these broad trends has made it into the headlines of the campaign yet. As E. J. Dionne of the Washington Post has pointed out, John McCain has fully embraced, even expanded, Bush's concept of a broad-gauge war on terror, declaring that "the transcendent challenge of the 21st century is radical extremism." But McCain has not said why he thinks that is, and Obama has not questioned this premise. Perhaps, like most Democrats, Obama suffers an insecurity complex about his national security credentials—especially going up against a Republican lion and war hero such as John McCain. Some Obama aides admit that he could put himself in political peril if he backs away from the "war on terror" construct. One top adviser to Obama conceded to me this week that "we have not as a party had this debate [about the war on terror]. We had an opportunity to have it in 2002, but it lasted about a day." Why? Because the Dems didn't want to look softer than Bush on terror.

It is a debate that only Obama can start. McCain won't bring it up. Nor will Hillary Clinton. Apart from being on the verge of oblivion politically, she is too fully vested in the war on terror, having voted in 2002 to authorize the war in Iraq as part of it. And if that debate doesn't start, we as a country will be effectively doomed to a "war" that has no prospect of ending. Bush has gradually expanded his definition of the war on terror to include all Islamic "extremists"—among them Hezbollah, Hamas, and other radical political groups that have no ties to Al Qaeda, ideological or otherwise. In doing so the president has plainly condemned us to a permanent war, for the simple reason that we will never be rid of all the terrorists. It is also a war that we will wage by ourselves, since no other nation agrees on such a broadly defined enemy. As Princeton scholar G. John Ikenberry has written, "It is perhaps a paradox—and one that is fitting for the strangeness of our current age—that we will need to end the war against terrorism because we cannot end terrorism."