I have my doubts about Sarah Palin as a potential presidential candidate, but you have to hand it to her: Her instincts are wonderfully diabolical. She's trapped our friends on the left in a no-win debate on American exceptionalism.

Nothing drives liberals battier. Some of them are prone to revolt at the mere suggestion that the United States has redeeming qualities.

Bill Maher's outburst on the Larry King show a few years ago is a sample: "You know, this country is - I've said this before, I'm going to keep saying it - it's a pitiful, helpless giant. ... It's a stupid country, with stupid people who don't pay attention."

Now, Maher is a comedian - a funny guy - and this really makes you smile, although he wasn't trying to be funny. I imagine he thought that with this little outburst, he could show everyone exactly how smart he is. Memo to Mr. Maher: You succeeded!

American exceptionalism usually isn't an issue in politics, but President Obama changed that. During a visit to France, he mishandled a question from a reporter who asked whether the president subscribes to "the school of American exceptionalism that sees America as uniquely qualified to lead the world." Obama said he believes in American exceptionalism, "just as I suspect that the Brits believe in British exceptionalism and the Greeks believe in Greek exceptionalism."

As James Q. Wilson noted drily in a Washington Post interview, Obama "did not understand how Americans feel about this."

Buried deep in the national psyche, the idea arises from the language of the Declaration of Independence - and from the notion that the settlers who came here, unlike other colonists, were concerned less with aping the mother country than with creating something better.

The French writer Alexis de Tocqueville, who journeyed to the United States in the 1830s, conveyed something of this spirit in his Democracy in America.

Obama himself noted the link between the declaration and the national character in his 2004 speech before the Democratic National Convention. Apparently, when he got the question in France, he forgot.

But let's consider the other part of the reporter's question - that American exceptionalism implies some sort of warrant to run the world. Actually, it doesn't, and I don't think the people that Tocqueville met would have made any such assertion.

America was still new and hardly a great power. But if I recall correctly from my reading of the book years ago, Americans had a very clear understanding that they had something going that was indisputably better than Europe and the rest of the world.

The run-the-world idea didn't arise from American exceptionalism, and it's possible to argue the opposite. Prior to World War II, many Americans believed that far from trying to run the world, we shouldn't get involved at all. We should hold ourselves apart.

Yet the isolationism that gripped the country in those years turned out to be a contributing cause of World War II. After the First World War, we retreated behind our ocean barriers, leaving the British and French - weakened by years of trench warfare - to supervise weak security arrangements that couldn't cope with the rise of Hitler.

By the time we got involved, things were too far gone to fix without massive sacrifice. We learned from our mistake. We were a great power, and everything done by a great power has consequences - including irresponsibly refusing to lead. Better to influence events and try to head off trouble.

While American exceptionalism doesn't necessarily qualify us to run the world, Palin's emphasis on the theme has prompted some commentators to assert their lefty bona fides with amusing articles asserting that we're really just another run-of-the-mill country. Headline on a recent Michael Kinsley piece in Politico: "U.S. is not greatest country ever."

The genius of Palin's strategy is that it also hints at the ambivalence many Democrats feel toward the use of military force. This is a party, after all, that has all but barred the old Truman Democrats - strong-defense figures like Sam Nunn or Scoop Jackson - from its presidential primaries.

Now we have a president who not only makes people wonder if he's ill at ease with one of the nation's basic ideas, but also makes noises as if he sincerely believes in the fairy tale of nuclear disarmament - and hires people who describe wars as "overseas contingency operations" or invent euphemisms for terrorism like "man-caused disasters."

Palin is plowing some very fertile political ground.

E. Thomas McClanahan is a member of the Kansas City Star's editorial board. He can be reached at mcclanahan@kcstar.com.