Obama's answer: "Well, the first thing we would have to do is make sure that we've got an effective emergency response -- something that this administration failed to do when we had a hurricane in New Orleans."

Asked to be commander in chief, Obama could only play first-responder in chief. Caught off guard, and without his advisers, he simply slipped into two automatic talking points: emergency response and its corollary -- the obligatory Katrina Bush-bash.

When the same question came to Hillary, she again pounced: "I think a president must move as swiftly as is prudent to retaliate." Retaliatory attack did not come up in Obama's 200-word meander into multilateralism and intelligence gathering.

These gaffes lead to one of two conclusions: (1) Obama is inexplicably unable to think on his feet while standing on South Carolina soil, or (2) Obama is not ready to be a wartime president.

During our 1990s holiday from history, being a national-security amateur was not an issue. Between the 1991 death of the Soviet Union and the terror attacks of 2001, foreign policy played almost no part in our presidential campaigns. But post-9/11, as during the Cold War, the country demands a serious commander in chief. It is hard to imagine that with all the electoral tides running in their favor, the Democrats would risk it all by nominating a novice for a wartime presidency.

Do the Democrats want to risk strike three, another national security question blown, but this time perhaps in a final presidential debate before the '08 election, rather than a midseason intraparty cattle call? The country might decide that it prefers, yes, a Republican -- say, 9/11 veteran Rudy Giuliani -- to a freshman senator who does not instinctively understand why an American president does not share the honor of his office with a malevolent clown like Hugo Chavez.