I'm not sure whether John Wilkes-Booth was a Republican. His shooting of Abraham Lincoln tends to indicate not. Lee Harvey-Oswald described himself as "a hunter of the fascists". That was after his defection to the Soviet Union. When Samuel Byck plotted to murder Richard Nixon, one can assume it was not Nixon's fanatical liberalism that offended him. Ronald Reagan's would-be assassin John Hinckley Jr reportedly acted out of an obsession with the actress Jodie Foster. None, to my knowledge, had any connection with Sarah Palin.
The reaction to Saturday's shootings in Arizona, or the left's reaction to the shootings, has been a case study in partisan, knee-jerk hysteria. In fact, it's been a case study in the sort of partisan, knee-jerk hysteria that is usually the preserve of the far right.
As nine-year-old Christina Taylor Green lay dying, there was no need to call the police. We already knew the culprits. "Glenn Beck guilty," tweeted Jane Fonda. "Mission accomplished, Sarah Palin," blogged Markos Moulitsas, founder of Daily Kos.
Let's for a moment set aside the sheer tastelessness of the attempt to appropriate mass murder for political purposes literally within minutes of it happening. Let's park the self-indulgence of people who claimed a shooting that robbed six families of children, fathers, mothers, husbands, wives and grandparents was "an attack on us all".
Those arguing the Arizona shootings are the product of US right-wing politics, and are demonstrative of a new culture of violent political intolerance, do not have a shred of evidence upon which to base their case. None. All they have to deploy are the same narrow-minded, reactionary, "guilt by association" smears that foster the very extremism they attempt to decry.
"The anger, the hatred, the bigotry that goes on this country is getting to be outrageous," said Arizona's Pima County sheriff Clarence Dupnik. At least Sheriff Dupnik can claim direct association with Saturday's appalling events, and the strength of his response is understandable. But factually, he is wrong. The last time the United States witnessed a sustained programme of organised political violence, bigotry and intimidation was in reaction to the civil rights advances of the 1950s and 1960s. And it was organised, endorsed and appeased by, among others, Southern Democrats.
The US does have a history of isolated attacks directed against its elected representatives. But the thing that connects almost every one of the perpetrators of those crimes is their easy access to guns. My understanding is that Gabrielle Giffords was an opponent of gun control. In 2008 her spokesman voluntarily told local media that she was the owner of a Glock pistol.
We should also remember there are those in the UK that carry guns. Two of them are the Special Branch officers currently detailed to escort our own Deputy Prime Minister, Nick Clegg, who has required their protection since voting to increase tuition fees. As we decry the political culture that begets violence in the States, perhaps we should cast a critical eye closer to home.
The US commentator Michael Tomasky is among many who have identified "the violent rhetoric that emanates from the right wing of American society" as contributing, even subliminally, to the shootings. But is "violent rhetoric" the preserve of the right? When John McDonnell expressed a desire to travel back in time and "assassinate" Margaret Thatcher, I don't recall the left rising in condemnation. Nor when Ken Livingstone expressed a wish to see the Saudi royal family swinging from lamp-posts.
The outcry from liberal commentators would at least have more weight if it carried the virtue of consistency. Instead, it is infected by hypocrisy. The very voices condemning the malign impact of Sarah Palin's website are the same ones that were raised in indignation when it was suggested that Pastor Jones, the Quran-burning preacher who was planning to march through Luton with the English Defence League, might be banned. Palin's graphics were deemed an assault on our freedoms. An intimidatory march through Britain's Asian communities is apparently fundamental to them.
Palin and Beck should be condemned, but not because their politics resulted in six people being shot dead in an Arizona shopping mall, appalling though that incident was. They need to be condemned because their politics leads to a quarter of a million people being killed in Iraq. Or because their policies on "abstinence" lead to hundreds of thousands dying of Aids. Or because their penal policies lead to thousands being executed by the federal state.
The American right is fast approaching its day of reckoning. It will be delivered not at the barrel of a gun, but at the ballot box. If we stoop to their level, all we will do is see that day delayed.