Despite that call for unity, Mr. Trump’s critics say he is responsible for the rise in racial division in the country. Among their examples: his false claims that President Barack Obama was not born in the United States; his campaign statement that Mexican immigrants were “rapists”; his claim that there were “very fine people on both sides” of a clash between white nationalists and counterprotesters in Charlottesville, Va.; and, most notably, his recent tweets saying four minority congresswomen should “go back” to their countries. (All are United States citizens, and three of them were born in America.)

What MR. CARLSON Said

If you were to assemble a list, a hierarchy of concerns of problems this country faces, where would white supremacy be on the list? Right up there with Russia, probably. It’s actually not a real problem in America.

White extremist ideology isn’t entirely to blame for mass shootings and other violence in recent years. No evidence suggests the Dayton gunman was a white supremacist, for example. But some of the deadliest mass shootings in this country, and elsewhere, have their roots in such beliefs, according to law enforcement experts, scholars and many independent news organizations.

Even Fox News itself has cited the existence of “white supremacy,” such as in headlines describing the man who drove through a crowd of demonstrators at the Charlottesville rally in August 2017, killing one.

The suspect in the El Paso shooting, the largest domestic terrorist attack against Hispanics in modern history , is believed to have posted a white supremacist manifesto online in which he wrote of a “Hispanic invasion of Texas.”

Critics like Ms. Sullivan of The Washington Post and the liberal watchdog group Media Matters pointed out that Mr. Carlson has used the word “invasion” multiple times when discussing immigration problems at the border. At one point Mr. Carlson said, “This is an invasion, and it’s terrifying.”

What MR. CARLSON Said

The combined membership of every white supremacist organization in this country would be able to fit inside a college football stadium.

According to the NCAA, the country’s largest college football stadiums hold about 100,000.

Bob Hopkinson, a spokesman for the Southern Poverty Law Center, which tracks hate groups, said tracking membership numbers is “extremely difficult.”

“Groups are either extremely private about membership numbers or they exaggerate them,” he said. “What we do know is that there are more than 300,000 people registered as users on the oldest hate site, Stormfront, and that number doubled when President Obama was in office.”