The Washington Post's E.J. Dionne Jr. thinks there's "something peculiar" about conservatives who turn "Islamic extremism into a mighty ideological force with the power to overrun the world."

In a way, he's right. There is indeed something peculiar about portraying "extremism," Islamic or otherwise, as an ideological movement of sufficient mass and might to capture the world. After all, "extremism" is something "extreme" practiced by, well, "extremists." You know -- a few far-out kooks on the margins. Why worry? There's always that disclaimer that we, as a post-9/11 society, invoke when we talk about "Islamic extremism" (or, plain "extremism," as President Bush now prefers): Namely, that such extremism has nothing doctrinally or traditionally to do with Islam as practiced by the rest of the world's billion-plus Muslims. So much more reassuring to see things this way, at least as long as no one notes that Sharia (Islamic law) is advanced by "extremism" and Islam alike.

Of course, if Western society understands "extremism" merely as a marginal phenomenon, little wonder Dionne thinks it's odd that so many conservatives take it seriously -- specifically, he writes, "Osama bin Laden's lunatic claims that he will build a new caliphate." Isn't Bin Laden just an extremist fruitcake on Islam's fringe, who, naturally, makes "lunatic claims"? It should take not a war to subdue him, but a warden.

Personally, I doubt so many conservatives really take the prospect of a Sharia-governed world seriously -- even a Sharia-governed Europe, or, for starters, a Sharia-governed Britain. And that goes whether such prospects are promulgated by a notorious Al Qaeda jihadist or the Archbishop of Canterbury. After all, the threat to Western-style liberty posed not only by violent "extremism" but by creeping Sharia -- with its dire implications for monogamy, women's rights, laws of evidence, freedom of belief and expression -- has never even made it into the rationale behind President Bush's so-called "War on Terror." It certainly hasn't been a topic on the campaign trail or most opinion pages. What seems to divide political thought these days is that conservatives still worry about "extremism" and liberals don't. Conservatives want to fight extremism in Iraq and Afghanistan, and liberals don't. Islam -- even as a, yes, democratically spread conduit of liberty-shrinking Islamic law -- is out of the political debate altogether.

Not surprisingly, then, Dionne thinks conservative concerns over mere "extremism" are a political liability that Democratic presidential candidates -- in their appeal to Americans bent on a leader "righting a jittery economy" and "rolling back extreme inequality" (did I miss the socialist takeover?) -- should exploit. Examining John McCain's stated belief that "radical Islamic extremists," or plain "extremists," pose the "transcendent challenge of the 21st century," Dionne argues that Democrats Hillary Clinton and Barack Obama should be knocking this contention, which seems to strike the liberal columnist as fantastic. He writes: "Does (McCain) mean that in the year 2100, Americans will look back and say everything else that happened in the century paled in comparison with the war on terrorism?"

Well, who knows? If, for example, Europe has become an Islamic continent by century's end, as predicted by the oft-cited Bernard Lewis, they just might. They might also wonder why in tarnation their post-9/11 forbears (us) failed to note the obvious connection between "extremists" like Bin Laden and the millions of ordinary Muslims who Islamized the European continent, which is a roughly shared devotion to Islamic law.

What's notable here is that Dionne, and, presumably some significant swath of liberal thought, don't see the war on terrorism as the stand-out priority even now. That's why he wants Democratic candidates attacking McCain on it. "If McCain's `transcendent challenge' claim falls apart on close examination," he writes, "the best rationale he has for his election would disappear."

In a way, he's right again. There is a transcendent challenge facing Americans, but we can't rise to it if our leaders can't explain it. President Bush certainly hasn't. To date, what should be a momentous civilizational debate -- liberty versus Sharia -- has fizzled into politically correct hemming and hawing over "extremism." This poses a transcendent challenge to McCain. Can he make it clear that such "extremism" is only a part of the problem? Does he even believe that? We urgently need to understand that Western-style liberty -- freedom of religion, freedom of conscience, freedom of expression, women's rights, equality before the law -- requires vigilance and protection in an era of advancing Sharia. And there's nothing "peculiar" or "odd" about that.