As President Trump and the media resume their war of words after a brief time-out, the furor over the attempted terror attacks has cast a harsh spotlight on the politics of violence.

The finger-pointing over the crude bombs sent to CNN, Barack Obama, Joe Biden, Hillary Clinton, other leading Democrats, and Robert DeNiro is not surprising, despite the inconvenient fact that we have no idea who the perpetrator is.

But it's unfolding against a long historical backdrop of partisans trying to seize the moral high ground and blame the opposition for "creating a climate" where a lunatic tries to kill people. And there is no shortage of examples of liberals and conservatives playing that card, depending on the target and the perceived ideology of the criminal involved (though these days the debate turns toxic before we even have a suspect).

In the latest round, things have gotten particularly heated between Trump and CNN, which evacuated its New York bureau after receiving one of the unexploded devices, which was addressed to John Brennan (who doesn't even work there).

At a Wednesday night rally, the president said that those in the political arena "must stop treating political opponents as being morally defective." His critics, naturally, think he should follow that advice.

But then Trump said this: "The media also has a responsibility to set a civil tone and to stop the endless hostility and constant negative and oftentimes false attacks and stories." If you took Trump out of it, most people would say yeah, there's too much hostility and negativity in the media. But coming from this president, it set off a sharp reaction — especially at CNN, whose president, Jeff Zucker, had already blasted the White House for not understanding the "seriousness" of slamming the media.

"They just sent a bomb to CNN, and the president doesn't say a word about that. And then tells us we are to blame," said anchor Chris Cuomo.

When a pipe bomb is sent to your place of employment, it's understandable that emotions would run high — and that journalists would invoke Trump's "enemy of the American people" rhetoric.

Sometimes we never know why nutjobs engage in mass slaughter. What was the motive of the Las Vegas shooter, who killed 55 people and wounded hundreds of others? I have no idea.

Here's a short history of how both sides seize on tragedy and violence for political purposes.

While the left is outraged at the explosives sent to famous Democrats and CNN, it was the right that was blaming liberal rhetoric last year when a gunman opened fire at a GOP baseball practice, nearly killing Steve Scalise and wounding several others. (In fairness, some prominent voices on the other side condemned both that shooting and this week's attacks.)

When police officers were killed during the Obama administration, some conservatives would go on the air and blame the president for not supporting law enforcement, even using the phrase "blood on his hands."

When an illegal immigrant was charged with killing San Francisco woman Kate Steinle in 2015, conservatives (including Trump) used her tragic death as a rallying cry against unlawful immigration and pushed Kate’s Law to tighten penalties on convicted criminals who reenter the U.S. illegally.

The entire country was saddened by the death of four Americans in the Benghazi attack. But that later morphed into years of Republican-led investigations to put more blame on Hillary Clinton.

The list goes on. Sarah Palin was not to blame for the deranged man who badly wounded Democratic congresswoman Gabby Giffords and others, even though she had put out a map with crosshairs over Democratic targets. The New York Times apologized last year for repeating that canard, and Palin's defamation suit did not succeed.

And when Timothy McVeigh blew up the Oklahoma City federal building, President Clinton singled out Rush Limbaugh for fostering a climate of hate, although McVeigh didn't need a radio talk show host to motivate him.

So guilt-by-association is, unfortunately, a common tactic. But that doesn't mean that media and political players — including those on Twitter — don't contribute to a toxic environment.

What would be healthy right now is for all sides to reexamine their behavior, rather than the reflexive attacks and counterattacks that have defined this president’s relationship with the press.