The steam seems to be going out of the move to “deftly pin this” — the shooting of Arizona congresswoman Gabrielle Giffords and 13 others — “on the tea partiers,” as one unidentified senior Democratic operative put it to Politico.

It has become obvious that the murderer was crazy, the follower of no political movement, motivated only by the bizarre ideas ricocheting around his head.

If any blame attaches to others, it is to authorities who had notice of his madness and did not do enough to confine him or prevent him from buying a gun. The Pima County sheriff, who was quick to suggest the attack was among the “consequences” of Republican rhetoric, also reported that the shooter’s bizarre behavior had been brought to the attention of authorities.

Arizona reportedly gives authorities more leeway than most states to put such individuals under restraint or at least prevent them from buying a gun. Perhaps there is some good reason this was not done — but at least there are questions that need to be asked.

Some broader perspective may be in order. The last congressman to be attacked by a gunman was California’s Leo Ryan, murdered at the Jonestown massacre in Guyana in 1978, 32 years ago.

Giffords’s “Congress on Your Corner” event was an effort to make herself available to constituents — a commendable thing, especially since many Democratic congressmen stopped making public appearances after they got negative feedback in summer 2009 town-hall meetings.

How many times have members of Congress made announced appearances, without security personnel, over the last 32 years? How many thousands? Tens of thousands?

The conclusion is that this kind of attack is, thank goodness, exceedingly rare — though not as rare as all decent people would like. There have been bitter political controversies and enormous amounts of political vitriol unleashed in American politics in those 32 years. And just one such attack — one too many, but only one.

Vitriolic rhetoric comes from all points on the political compass. But many in the media, when trying to assess blame for violent acts, have an impulse to look for it only on the right.

Thus the impulse to identify as Tea Party types the man who crashed a plane into the Austin IRS office, the Pentagon subway shooter, the Discovery Channel hostage taker.

Or the impulse to insist that conservatives intend the military metaphors with which political discourse is riddled — campaign, targeting, the war room — be taken literally.

Actually, we do know of societies where people on one side of the political divide encourage and sponsor assassinations of people whom they oppose.

This was Germany in the years after World War I, when those who thought Germany had been stabbed in the back hailed the assassination of the industrialist and moderate (Jewish) politician Walter Rathenau in 1922 — including a failed painter from Vienna named Adolf Hitler.

This was Japan in the 1930s, when advocates of military aggression systematically assassinated moderates who wanted their country to live in peace with its neighbors and not seek conquests abroad.

Or, to take an example from last week, Pakistan, where the governor of Punjab was assassinated. His offense: opposing blasphemy laws that carried a death penalty. Those who supported his assassination celebrated publicly and urged more such killings.

Systematic political assassination can be effective, with horrifying results, as the examples from Germany and Japan show.

And the example from Pakistan shows that President Obama, his administration, and members of Congress have a very difficult problem on their hands, more difficult since the sudden death last month of our able diplomat Richard Holbrooke.

Suggestions that the shooting in Arizona are of the same ilk as these is something of a blood libel against politicians of all stripes in our country and against the American people. No American politician, no significant segment of any political movement, no statistically identifiable share of the American people wishes the violent death of its political opponents.

Vivid political rhetoric is always in season, and has been for all the years of our republic. And military metaphors are part of the language of our politics — metaphors that no serious person takes literally. We should not let it be otherwise, even as we wish for the full recovery of Gabby Giffords and the others stricken and mourn those lost.

— Michael Barone is senior political analyst for the Washington Examiner. © 2011 The Washington Examiner.