Jan. 12, 2010 -- An aide close to Sarah Palin says death threats and security threats have increased to an unprecedented level since the shooting in Arizona, and the former Alaska governor's team has been talking to security professionals.

Since the shooting in Tucson, Palin has taken much heat for her "crosshairs" map that targeted 20 congressional Democrats in the 2010 mid-term election, including that of Rep. Gabrielle Giffords, who was the main target of Saturday's attack.

Friends say Palin, a possible 2012 contender, was galled as suggestions of her role in the tragedy have swirled.

Palin responded in detail today to the attacks leveled against her, but while her intentions may have been to shift the blame away from herself, she instead put her in the hot seat again.

"Journalists and pundits should not manufacture a blood libel that serves only to incite the very hatred and violence they purport to condemn," she said in an early morning Facebook post today.

The term "blood libel" has been used historically to falsely accuse Jews of using Christian children's blood to prepare their Passover matzoh. The myth is said to have begun in Europe as early as the 12th century, perpetuated by the death of a small boy in England in 1144.

It's a term that Jews say has been used to incite anti-Semitism and justify violence against them for centuries.

Palin's use of the word has triggered some deep emotions, even among those who believe Palin has been a target of unfair criticism since the Tucson shooting.

The Jewish Fund for Justice assailed Palin for abusing a tragic episode in Jewish history.

"We are deeply disturbed" by her commentary, president Simon Greer said in a statement today. "Unless someone has been accusing Ms. Palin of killing Christian babies and making matzoh from their blood, her use of the term is totally out of line."

The National Jewish Democratic Council called the video a step in the wrong direction.

"This is of course a particularly heinous term for American Jews, given that the repeated fiction of blood libels are directly responsible for the murder of so many Jews across centuries -- and given that blood libels are so directly intertwined with deeply ingrained anti-Semitism around the globe, even today," it said in a statement.

"The last thing the country needs now is for the rhetoric in the wake of this tragedy to return to where it was before," liberal group J Street said in a statement. "We hope that Governor Palin will recognize, when it is brought to her attention, that the term 'blood libel' brings back painful echoes of a very dark time in our communal history when Jews were falsely accused of committing heinous deeds."

But not all Jews are offended by the term. Liberal political commentator and Harvard Law professor Alan Dershowitz pointed out that the term has been used frequently as a metaphor and in a broader context.

"The term 'blood libel' has taken on a broad metaphorical meaning in public discourse," he said in a statement to biggovernment.com. "I myself have used it to describe false accusations against the State of Israel by the Goldstone Report. There is nothing improper and certainly nothing anti-Semitic in Sarah Palin using the term to characterize what she reasonably believes are false accusations that her words or images may have caused a mentally disturbed individual to kill and maim."

Palin's Use of the Term Blood Libel Stirs Emotions

When asked by ABC News why the former Alaska governor chose the term "blood libel," a Palin aide responded with Dershowitz's comments and a list compiled by the National Review of recent examples of the use of "blood libel" in the media.

Conservative writer Glenn Reynolds first used the term Monday in a Wall Street Journal op-ed to defend Palin.

"So as the usual talking heads begin their 'have you no decency?' routine aimed at talk radio and Republican politicians, perhaps we should turn the question around," Reynolds wrote. "Where is the decency in blood libel?"

Politicians on both sides of the political aisle have been, for the most part, mum on the issue, although Rep. James Clyburn, D-S.C., did imply today that Palin likely didn't understand the implications of using such a heavy-handed term.

"Intellectually, she seems not to be able to understand what's going on here," Clyburn said in a radio interview.

ABC News' Mary Bruce contributed to the report.