Late last week, as the nation learned that a Donald Trump supporter was arrested for targeting Democratic leaders with pipe bombs, Republicans quickly embraced a specific, but badly flawed, talking point.

White House Press Secretary Sarah Huckabee Sanders told reporters, "The president is certainly not responsible for sending suspicious packages to someone, no more than Bernie Sanders was responsible for a supporter of his shooting up a Republican baseball field practice last year."

It wasn't long before Sen. Lindsey Graham (R-S.C.) and other Republicans quickly embraced the talking point. That was unfortunate:. Sen. Bernie Sanders (I-Vt.) has never encouraged or applauded political violence. Trump has done both.

As the Washington Post noted, the president tried to take this line of defense in a new direction last night.

President Trump complained Monday about the news coverage he has received related to the alleged pipe bomber, saying a different standard was applied to then-President Barack Obama when nine black worshipers were killed at a church in Charleston, S.C., during his tenure. Trump highlighted the contrast during a wide-ranging interview with Laura Ingraham of Fox News, who pointed out that Cesar Sayoc, who allegedly sent more than a dozen mail bombs to leading Democrats and CNN, was a big Trump fan. None of the devices exploded. "I was in the headline of The Washington Post, my name associated with this crazy bomber," Trump said. "They didn't do that with President Obama with the church, the horrible situation with the church -- they didn't do that."

It's true that news organizations didn't draw any associations between Barack Obama and Dylann Roof after he gunned down innocents in an African-American church in 2015. It's also true that this wouldn't have made any sense.

Roof, in case anyone's forgotten, was a white supremacist. He was no fan of the Democratic president and he felt no need to go after Obama's perceived domestic opponents.

Does Trump not see how these two cases are different?

By the Republican's reasoning, Obama wasn't held responsible for a mass shooting that happened during his presidency, so Trump shouldn't be held responsible for a series of assassination attempts that happened during his presidency.

But this spectacularly misses the point. Questions about Trump's culpability have nothing to do with timing and everything to do with his record. The Republican stands accused of legitimizing political violence and, as a Washington Post report put it over the weekend, fostering a "toxic environment" that has had the effect of allowing violence to flourish.

No one has ever even accused Barack Obama or Bernie Sanders of such tactics. Someone probably ought to explain this to the president the next time he starts whining about a double-standard that obviously doesn't exist.