During an appearance in Philadelphia last month, Hillary Clinton introduced a controversial couple as part of her presidential campaign. She defended them as victims of smear attacks. "Valerie and Joe have had their patriotism questioned," she insisted. "They have been maligned as un-American because they believed  that President Bush was waging a preemptive war that was not in America's interests and now because we believe our troops should not police Iraq's civil war."

Of course this wasn't true. Both Valerie Plame and Joe Wilson were accused of being untruthful (and shameless self-promoters), not unpatriotic. Plame was a CIA official who blamed the Bush White House for revealing her identity to the media in retaliation against her husband. Wilson claimed the president lied about Saddam Hussein's efforts to obtain uranium in Africa. Actually, Bush was correct. Saddam had sought uranium in Africa. And Plame's identity had been leaked not by vengeful Bush aides but by a State Department official who was an Iraq war skeptic like Plame and Wilson.

The episode had a familiar ring, the ring of patriotism paranoia. When criticized for being soft or wrong on national security, Democrats routinely respond that their patriotism is being questioned. In fact, they're rarely if ever accused of being unpatriotic. But to the paranoid, that's immaterial.

John Kerry went so far in 2004 as to insist he knew how the Bush crowd would respond even before he delivered a foreign policy speech. "I know what the Bush apologists will say to this--that it is unpatriotic to question, to criticize, or to call for change," he said. Of course, Bush and his allies said nothing of the kind.

There's method in the Democrats' paranoia. They've figured out how to use it to their advantage: Blame someone for calling you unpatriotic, and you may blow off their legitimate criticism, even stigmatize them as smear artists, while you're seen responding more in sorrow than in anger.

Now Barack Obama has picked up the I'm-being-called-unpatriotic theme. Practically no one has questioned his patriotism, aside from a few bloggers and a stray TV commentator or two. Nonetheless, he declared after the Texas and Ohio primaries, "In this campaign, we will not stand for the politics that uses religion as a wedge and patriotism as a bludgeon." A few weeks later, Obama campaign manager David Plouffe chimed in: "Questioning patriotism is something we don't think has a place in this campaign."

Obama has taken what he calls "the patriotism thing" a step further. He's suggested the patriotism of his political opponents pales in contrast with his "true patriotism." At least that was how he explained his decision to remove his American flag lapel pin.

"You know, the truth is that right after 9/11, I had a pin," Obama said. "Shortly after 9/11, particularly because as we're talking about the Iraq war, that became a substitute for I think true patriotism, which is speaking out on issues that are of importance to our national security, I decided I won't wear that pin on my chest." In effect, Obama turned the patriotism issue on its head. If anyone was unpatriotic, it was his critics and foes, certainly not Obama.