on a day set aside for healing and prayer in the wake of last weekend's mass shooting in Tucson, all vestiges of a political armistice were shattered when Sarah Palin, the former Alaska governor, issued a video message accusing her critics of committing "blood libel" against her.
In a nearly eight-minute video posted on Facebook that veered between defiant and defensive, the Tea Party figurehead broke her days-long silence to answer allegations that her own rhetoric and the passions stirred by the Tea Party had somehow propelled the man accused of Saturday's carnage that left six dead and critically wounded congresswoman Gabrielle Giffords.
Her video was posted just hours before President Barack Obama, in the role of healer-in-chief was to address a memorial event at the University of Arizona in Tucson, and John Boehner, the new House Speaker, opened a day of debate and reflection on the floor of the House of Representatives as Ms Palin's video played.
"We feel a litany of unwanted emotions that no resolution could possibly capture," Mr Boehner said, exhibiting with tears and snuffles his propensity for public emotion. "We know that we gather here without distinction of party; the needs of this institution have always risen above partisanship."
Ms Palin, seen as a likely Republican candidate for president in 2012, had been under pressure to respond publicly to the criticisms piled on her since the Tucson shooting, notably linked to a map posted by her political action committee last year that used cross-hair symbols to identify districts with vulnerable Democrat incumbents before last year's midterm elections. One was Ms Gifford's.
Her statement may have had a greater impact than she expected because of her citing "blood libel", a phrase associated with the centuries-old slander of Jews that they used the blood of Christian children in their rituals and one used as a pretext for anti-Semitic persecution. Some Jewish leaders objected to her using the phrase. Ms Giffords, still in intensive care, is Jewish.
In her video, shot before a stone fireplace and an American flag, Ms Palin rejected the case for drawing a link between the attempted assassination of Representative Giffords and the heated rhetoric of political debate in last year's campaigns. She had listened to commentary on the killings, she said, "at first puzzled, then with concern and now with sadness to the irresponsible statements from people attempting to apportion blame for this terrible event... Within hours of a tragedy unfolding, journalists and pundits should not manufacture a blood libel that serves only to incite the very hatred and violence that they purport to condemn. That is reprehensible.
"There are those who claim political rhetoric is to blame for the despicable act of this deranged, apparently apolitical criminal," Ms Palin went on. "And they claim political debate has somehow gotten more heated just recently. But when was it less heated? Back in those 'calm days' when political figures literally settled their differences with duelling pistols?"
Violent acts, she went on, should be blamed on the perpetrators only. "They begin and end with the criminals who commit them, not collectively with all the citizens of the state, not with those who listen to talk radio, not with maps of swing districts used by both sides of the aisle, not with law-abiding citizens who respectably exercise their First Amendment rights at campaign rallies."
While the fairness of pointing a finger at Ms Palin will be fiercely debated, her standing may already have suffered serious damage, possibly not helped by a statement that seemed more focused on her than on the derad and 14 wounded victims of the assault. "Instead of dialling down the rhetoric at this difficult moment, Sarah Palin chose to accuse others trying to sort out the meaning of this tragedy of somehow engaging in a 'blood libel' against her and others," David Harris, president of the National Jewish Democratic Association said of the governor's video. "This is, of course, a particularly heinous term for American Jews."
Mr Obama was expected last night to say nothing in his speech that could be interpreted as partisan. His challenge was to make a speech that will be remembered as uplifting and inspiring at a time of tragedy. The address is inevitably going to be compared to the widely praised words of Bill Clinton in 1995 after the bombing of a federal building in Oklahoma that claimed 168 lives, including 19 children under six, and injured more than 680 people.
Mr Obama's predecessor, George W Bush, faced a similar challenge in the aftermath of the 11 September 2001 attacks, when he stood in the rubble of Neqw York's World Trade Center, speaking through a bullhorn.