Going by objective standards of reason and fairness, Al Sharpton is not to blame for the assassination of two New York City cops over the weekend. Nor are New York Mayor Bill de Blasio, U.S. Attorney General Eric Holder, President Obama or any of the protesters and activists they supported, encouraged and allied themselves with. Going by what we know, the only person to blame is the man police identified as the killer, Ismaaiyl Brinsley.

This is the standard I’ve upheld in this space for years, when one madman after another has killed and maimed in the name of one cause or another. It’s also been necessary to uphold this standard when madmen have killed for no political cause whatsoever, but politicians and journalists have been determined to claim otherwise.

The most glaring example of this was the horrible 2011 shooting spree in Tucson that claimed six lives and horribly wounded then-U.S. Rep. Gabrielle Giffords. The shooting occurred during a period of maximum liberal paranoia about the tea party movement. And in a riot of groupthink, much of the elite media convinced itself – absent any evidence – that the killer, Jared Loughner, was inspired by, variously, Sarah Palin’s Facebook map of congressional races (there were targets over various districts where Palin wanted Democrats defeated), Minnesota Rep. Michele Bachmann’s overheated speeches and other forms of what New York Times columnist Paul Krugman called “eliminationist rhetoric.”

Indeed, Krugman’s response to the Tucson shooting was indicative of this thinking. In a column titled “Climate of Hate,” Krugman began: “When you heard the terrible news from Arizona, were you completely surprised? Or were you, at some level, expecting something like this atrocity to happen? Put me in the latter category.”

In other words, Krugman, like countless others, had his explanation ready before the event even transpired.

This has become something of a cottage industry for some left-wing activist groups, eager to implicate their political opponents in murder. No doubt this knee-jerk reaction is often sincere. When a radical Islamic terrorist left a bomb in Times Square, then-New York Mayor Michael Bloomberg no doubt meant it when he speculated that the culprit was an opponent of Obamacare.

And some claim conservatives do the same thing when it comes to terrorist attacks from Muslims. But that strikes me as something categorically different. radical Islamic mass murders, both attempted and successful, in recent years were done in the name of an international movement, often with material, technical or spiritual assistance from abroad.

The 2009 Fort Hood shooter was in contact with al-Qaeda and later admitted his murder rampage was on its behalf. And, unlike the tea party crowd, al-Qaeda actually uses “eliminationist rhetoric” – and not just rhetorically.

And yet, in such cases, the knee-jerk response of the Obama administration and many liberals is to counsel the very restraint they deny to their domestic political opponents. They try to minimize the event as an “isolated incident.” Amazingly, the administration designated the Fort Hood killing “workplace violence.” (Congress just passed legislation, overruling the administration, that would make victims of the attack eligible for Purple Hearts).

Now we have two New York City policemen dead. The killer’s postings on social media make it abundantly clear he was motivated in part by the intense furor over the deaths of Michael Brown and Eric Garner. One of Sharpton’s “Million Marchers” mobs reportedly even chanted, “What do we want? Dead cops! When do we want them? Now!”

Going by the standards liberals established, Sharpton clearly has blood on his hands (for this cop-slaying and other hate crimes from his earliest days as a race hustler). And the blame hardly ends there if you go by the rules that were applied to Palin and others.

But here’s the problem: Those rules stink.

Sharpton is a special case; he should have been pelted from the public stage decades ago. But it would be ridiculous to believe that De Blasio or Holder – or Obama – wanted this tragedy.

Double standards are seductive. If you’ve been demonized unfairly, it is only human to turn the tables at the first opportunity. Giving in to that temptation, however, leads to madness. Conservatives should take the high road – and liberals should join them – the next time a madman gives them an opportunity to take the low road.

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