But the invocation of “lynching” to characterize a legislative process explicitly sanctioned by the Constitution marks a new, racially insensitive show of malice by the president toward lawmakers’ efforts to remove him from office.

According to an online archive of Trump's social media feed, he only tweeted the term on one other occasion, in a September 2015 post praising conservative radio host Mark Levin.

Throughout his 2016 campaign and continuing into his presidency, Trump has been accused of fomenting racial animus and assailing his Democratic rivals with racist or crass criticisms.

Over the summer, Trump faced widespread condemnation for calling into question the patriotism of four freshman congresswomen of color, tweeting that those U.S. citizens should “go back” to their countries of origin.

Trump was also rebuked for attacking the late African-American Rep. Elijah Cummings (D-Md.) as “racist” and “a brutal bully,” and charging that his predominantly black, Baltimore-based congressional district was “a disgusting, rat and rodent infested mess” where “no human being” would want to live.

House Majority Whip Jim Clyburn (D-S.C.), the highest-ranking African American in Congress, denounced Trump's tweet Tuesday, telling CNN that the three American presidents who previously faced impeachment threats would not have likened their situations to lynchings.

“I really believe this man is prone to inflammatory statements, and that is one word no president ought to imply on himself,” he said. “I’ve studied presidential history quite a bit, and I don’t know if we’ve ever seen anything quite like this. Andrew Johnson never would’ve described what was happening to him this way, and certainly Bill Clinton didn’t, nor did Nixon. This president is hopefully an anomaly.”

Clyburn added: “I’m a product of the South. I know the history of that word. That is a word that we ought to be very, very careful about using.”

Several other black lawmakers expressed similar outrage at the president’s analogy.

“You think this impeachment is a LYNCHING? What the hell is wrong with you?” tweeted Rep. Bobby Rush (D-Ill.), a civil rights activist who co-founded the Illinois chapter of the Black Panther Party. “Do you know how many people who look like me have been lynched, since the inception of this country, by people who look like you. Delete this tweet.”

“I don't know how many times we have to say that the President is racist and unfit to serve,” Rep. Bennie Thompson (D-Miss.) wrote online.

And Rep. Karen Bass (D-Calif.) asked incredulously: “You are comparing a constitutional process to the PREVALENT and SYSTEMATIC brutal torture of people in THIS COUNTRY that looked like me?”

Rep. Ilhan Omar (D-Minn.), a Somali refugee and one of the quartet of progressive female House members who the president targeted in July, called Trump “the chief of command for white supremacists,” telling reporters in the Capitol: “For him to invoke lynching is quite telling.”

Rep. Adam Kinzinger (R-Ill.), one of the few House GOP lawmakers who has shown a willingness to scold Trump’s tone on Twitter, also panned the president’s post.

“We can all disagree on the process, and argue merits. But never should we use terms like ‘lynching’ here,” he tweeted. “The painful scourge in our history has no comparison to politics, and @realDonaldTrump should retract this immediately. May God help us to return to a better way.”

In other tweets Tuesday morning, Trump touted his approval rating among Republican voters, referenced various “Fox & Friends” segments, and applauded GOP support for a failed resolution to censure House Intelligence Chairman Adam Schiff (D-Calif.) — one of the leaders of the impeachment probe.

Abbey Marshall and Sarah Ferris contributed to this report.