So why do Democrats feel so vulnerable on the issue of patriotism? This question takes us back to the 1960s and, yes, Vietnam. That war, which a Democratic president escalated, split the party, costing it the presidency in 1968. By 1972 the countercultural left was firmly established as a part of the Democratic coalition--and it remains so. A significant and vocal minority of the party, that is, believes that America is imperialistic, racist, militaristic, oppressive, etc. These views aren't necessarily unpatriotic; it is possible to love one's country and also be a harsh critic of it. But if dissent can be patriotic, assent is far less complicatedly so.

That's especially true during wartime, when domestic disunity can aid the enemy. Several men who were prisoners of war in Vietnam have said their communist captors used tapes and transcripts of Mr. Kerry's antiwar testimony in an effort to demoralize them during interrogation sessions. These days, overseas opponents of America's war effort cite the agitprop movie "Fahrenheit 9/11" as if it were authoritative--and the Democrats treated the maker of that film as a hero at their convention, where he was an honored guest of Jimmy Carter.

After the Sept. 11 attacks, it seemed possible that the antiwar counterculture was a thing of the past. But old habits die hard, and for the most part the Democratic left soon returned to its Sept. 10 mindset. Democrats nominated John Kerry, respected on the left for his antiwar agitation, on the theory that his war-hero pose would establish his patriotism and be sufficient to compensate for his lack of a muscular foreign policy.

Instead it has raised questions about his character. One veteran quoted in "Unfit for Command" puts the matter pungently: "In 1971-72, for almost 18 months, he stood before the television audiences and claimed that the 500,000 men and women in Vietnam, and in combat, were all villains--there were no heroes. In 2004, one hero from the Vietnam War has appeared, running for president of the United States and commander in chief. It just galls one to think about it."