Sarah Palin's defining moment?

Former Alaska Gov. Sarah Palin made headlines in the aftermath of the Arizona shootings by using the term "blood libel" to describe comments by those who tried to link conservatives to the assassination attempt against Rep. Gabrielle Giffords.

Some Jewish groups protested the term, which historically had been used to accuse Jews of using the blood of Christians in religious rituals. But it wasn't just Jewish groups. Many commentators noted that Palin's speech was in poor taste generally, coming as it did on the same day as President Obama's speech at a memorial to the shooting victims in Tucson.

Add to the mix the fact that Obama's speech has been hailed as perhaps one of the best of his presidency. Even commentators like Glenn Beck, Charles Krauthammer, and Brit Hume praised it. The net effect is that, by comparison, Palin looked decidedly un-presidential. James Fallows, commenting on National Public Radio, said what Palin critics and even some Palin supporters felt: "I had the sense that I was watching a moment very much like . . . Edmund Muskie crying on the New Hampshire campaign trail in 1972, or when Howard Dean had his scream."

Fallows was referring to a moment early in the 2004 Democratic presidential primary season when Dean, who had been leading in the polls, suffered a disappointing third-place finish in Iowa. During his concession speech, Dean attempted to fire-up his demoralized troops: "We're going to South Dakota and Oregon and Washington and Michigan, and then we're going to Washington, D.C., to take back the White House! YEAH!"

The problem was that Dean, who had been suffering from the flu and was physically exhausted, looked disheveled. He contributed to the image of disarray by shedding his suit jacket and rolling up his sleeves. And his "YEAH!" sounded . . . well . . . weird, even animal-like. It was immediately dubbed the "Dean Scream" and it became a defining political moment. Dean ended his campaign less than a month later.

Such moments are not uncommon in politics. Fallows also mentioned Muskie. When a New Hampshire newspaper reported that Muskie's wife, Jane, drank and used off-color language during the campaign, the Democratic presidential candidate confronted reporters outside the newspaper's offices during a snowstorm. The press reported that Muskie broke down and cried, though Muskie claimed the "tears" were melted snowflakes. Nonetheless, the damage was done. Muskie already had a reputation as a man with a fiery temper and one who was possibly unstable. This moment fed those fears.

There are Republican examples, too. Consider Dan Quayle and George Allen. Vice President Quayle, who was battling an image as an intellectual lightweight, was caught on camera in 1992 misspelling the word "potato" in an elementary school classroom. That moment likely cost him a run for the presidency and weakened his boss, George H.W. Bush, who failed to win reelection. George Allen, the former U.S. senator and governor of Virginia, spotted a Democratic operative at one of his rallies and called him "Macaca," a word that some judge as a racial slur, and his bid for reelection to the Senate failed and any shot he had for the White House ended before it got a good start.

All of these moments say more about the state of politics than they do about the candidates whose careers they derailed. But the moments became emblematic because they tapped into deep stereotypes. Allen, a Southerner, was assumed to be a racist. Here was "proof." Quayle, the youngster, was assumed to be incompetent. Here was "proof."

So what will Palin's "blood libel" moment "prove" about her? Some are saying that she relies too heavily on a small, sycophantic staff that is "not ready for prime-time." Some say that her inflammatory comments are designed to fire up her political base but will never play to the broad mainstream of the American people. Yet others say she is an opportunist, a headline hog, in it for the money and the fame.

Will the "blood libel" comment "prove" these criticisms? Or will this moment become an opportunity for Palin to step-up her game? In a year, when we are well into the presidential primary season, will we-as Fallows predicts-look back on "blood libel" as Palin's "Dean Scream" or her "Macaca Moment," or will this episode be remembered as the moment Palin decided she was no longer content to be a celebrity and transformed into a leader?

Only time, and what Sarah Palin does next, will tell.