Let’s acknowledge up front that the right does not have a monopoly on political violence. Last year a leftist, James Hodgkinson, opened fire on Republican congressmen as they practiced for a charity baseball game, wounding several people, most seriously Representative Steve Scalise of Louisiana. In response to her vote to confirm Brett Kavanaugh to the Supreme Court, Senator Susan Collins, Republican of Maine, received a threatening letter that claimed to contain ricin. (Tests showed it didn’t.) In what appears to be a separate incident, a 74-year-old Long Island man was arrested this month on charges of threatening senators with death if they voted for Kavanaugh.

These acts should be condemned unreservedly. But there is no serious comparison between left-wing and right-wing violence in this country, either in the scale of the phenomenon or the degree to which it is encouraged by political leaders.

According to a report by the Anti-Defamation League, white supremacists were responsible for 18 of 34 “extremist-related murders” in the United States in 2017. Over the last decade, the report says, people on the far right were responsible for 71 percent of extremist killings. (Radical Islamists committed most of the rest.)

The violent part of the right is integrated into the Republican Party in a way that has no analogue on the left. A few months before the Unite the Right white nationalist rally in Charlottesville, Va., that devolved into a deadly riot, Corey Stewart, now the Republican candidate for Senate in that state, appeared at an event sponsored by one of Unite the Right’s organizers, Jason Kessler. (He’s since disavowed both Kessler and Paul Nehlen, a white nationalist he once described as a “personal hero.”) One rallygoer, James Allsup, had been president of the Washington State University College Republicans. He stepped down amid the ensuing controversy, but was later elected a precinct committee officer by his local party organization. (The Republican National Committee has denounced him.)

In a video extolling violence, Gavin McInnes, the founder of the violent right-wing street gang called the Proud Boys, proclaimed, “Fighting solves everything.” This month, he was invited to speak at the Metropolitan Republican Club, a G.O.P. clubhouse on the Upper East Side, where he reportedly re-enacted the 1960 murder of a Japanese Socialist Party leader.