Proponents of each example have a specific response in mind. If Iraq is Vietnam, we allegedly have no choice but to give up in Iraq. If the war on terror is like the Nazi menace, it's time to wax Churchillian.

But what if there are historical parallels lurking in the shadows of our ignorance? What if the jihadists are more like the Muslim Barbary pirates made famous in the Marine Hymn with the line about "the shores of Tripoli"? Or maybe they're more like the Thugees, an 18th-century murder cult in colonial India. Or the Panslavist Black Hand. Or a radical faction of the youth group Up With People. OK, I'm kidding about that last one. The point is, we don't know. But surely the ocean of historical experience cannot be summed up by the tributaries of Vietnam and Nazi Germany.

The second problem is that although Burke was right that human nature has no history, technology does. Newsweek's Fareed Zakaria penned a thoughtful essay debunking the 1938 analogy. Iran is an economic and military weakling compared with the Third Reich. Inflating Ahmadinejad into Hitler stretches the analogy to the breaking point. Fair enough, but Ahmadinejad has options Hitler didn't. Der Fuehrer needed a strong economy and an enormous military to accomplish his objectives. Thanks to nuclear and (soon) biological weapons, second-rate powers like Iran, as well as basket cases like North Korea and modern-day Thugees like Bin Laden, can quickly attain destructive power Hitler only dreamed of. As science proceeds, this reality will loom ever more frightening.

Maybe Chase's conviction that history provides few solutions is finally vindicated, as weapons of mass destruction are something new under the sun. It's ironic that just when the left has come to admire the utility of history, history may be offering us a blank page. The sobering question is: What kind of analogy will we provide for future generations?