Of all the voices being raised against the specter of mob rule in this country, few carry more weight than that of Steve Scalise.

That’s because Mr. Scalise, a Republican congressman from Louisiana, knows first-hand what happens when violent words turn into violent action.

In June 2017, he was shot and seriously wounded by a man named James Hodgkinson, who turned up at a practice session for a charity baseball game in Washington, D.C. — and started shooting as players praticed in Alexandria, Virginia, Mr. Scalise wound up in intensive care, underwent multiple surgeries and even had to relearn how to walk.

And all because Mr. Hodgkinson, a Bernie Sanders supporter described by his own lawyer as “a very irascible, angry little man,” was so furious over the election of President Trump that he moved to the D.C. area to protest.

Well, I think we can all agree that there’s a huge gap between the all-American tradition of protesting and the criminal activity of trying to maim or murder those you disagree with.

At least I hope we can agree on that. After all, when you have Eric Holder, President Obama’s attorney general, caught on tape telling his political teammates, “When they go low, we kick them,” you have to wonder.

Especially when Mr. Holder’s advice follows viral videos of Brett Kavanaugh protesters ambushing lawmakers in hallways and elevators and being verbally abusive, not to mention accosting others in restaurants and even at their homes.

You’d think that the Scalise shooting would have made everyone wary of ratcheting up the rhetoric too much. And sure, some did speak up against it — at least a little bit. Mr. Sanders said he was “sickened by this despicable act,” and Michelle Obama has famously said, “When they go low, we go high.” Even Mr. Holder felt pressured to walk back his advice as something not meant to be taken literally.

But these calls for civility have been far too few in number. And as the fight over Justice Kavanaugh proved, they obviously haven’t made much of an impression.

Indeed, many on the left have made a point in recent weeks of denouncing calls for civility. In angry posts on Facebook, Twitter and elsewhere, they insist that this is nothing more than an attempt to muzzle them. Faced with a president who is alleged such a monster, they claim they have no choice — that they must resort to profane rhetoric and physical confrontation. That those who support the president will have “no peace.”

As Rep. Maxine Waters, California Democrat, put it: “If you see anybody from [the Trump administration] in a restaurant, in a department store, at a gasoline station, you get out and you create a crowd! Tell them they’re not welcome anymore, anywhere!”

Well, there’s another name for angry crowds: Mobs. The left doesn’t like the “m word,” but that doesn’t change the fact that it’s accurate. And when you keep demonizing your opponents, no matter how justified you may think it is, don’t be surprised when — having let the genie out of the bottle — things get ugly.

Just ask Steve Scalise. “I’m concerned that you are seeing an increase of this,” he said recently. “I’d like to see the mainstream media asking both Republican and Democratic leaders to stand up against this kind of rhetoric, this kind of violence.”

That, he adds, is why “we’ve got to keep shining a light on this, to make it clear that this isn’t what politics is about in America. It’s not what the founding of our country was about. It was about freedom of speech, freedom of expression. Not violence against anybody.”

Contrast that with Hillary Clinton, who recently said, “You cannot be civil with a political party that wants to destroy what you stand for, what you care about.” And what would she suggest instead? Oh, “civility can start again,” she says — once her party is back in power.

Such threats are unconscionable. Those who support such a belligerent agenda don’t deserve the reins of power. It’s un-American. And it’s wrong.