WASHINGTON — Mr. Civility had had enough.

"We don't ever, ever want to pass up, it seems, an opportunity to escalate," Rep. Emanuel Cleaver II, D-Mo., said from the House speaker's chair Tuesday afternoon after a fight broke out over a resolution to condemn President Donald Trump's "racist tweets."

The House went silent as the mild-mannered Cleaver, a seven-term House member, swept a pointed finger across the chamber, saying he dared anyone to say he had been "unfair."

"We want to just fight," Cleaver, a pastor, said, balling his fists to demonstrate the exchanges. Then, in a move that House veterans said they had never seen before, he declared, "I abandon the chair," put down the gavel and strode off.

The dramatic moment came during an emotional debate over President Donald Trump's racist tweets advising four Democratic congresswomen of color to "go back" to where they came from. Trump also cast them as haters of America, Israel and Jews. But it also reflected Cleaver's longtime emphasis on the need for civility, to which he devotes a page of his House website and about which he tweets every Friday.

"Our differences only become virtuous when we discuss them with civility and statesmanship," he writes on his website. "When we allow hyperpartisanship to control the conversation, what once was a virtue becomes the downfall of a divided nation."

Condemnation has thundered in over three days from Democrats and a few Republicans. Trump offered no apologies, adding that the four congresswomen can leave the United States if they have complaints.

House Speaker Nancy Pelosi, D-Calif., brought a resolution to the floor to formally condemn Trump's remarks, which Trump had tried to warn Republicans away from supporting.

Then the upheaval began. Republicans formally objected after Democratic Rep. Eric Swalwell of California repeated Trump's reference to African nations as "shithole countries," one of several examples he read and called "racist."

They also objected after Pelosi said during a floor speech of Trump's remarks: "His comments from the White House are disgraceful and disgusting, and the comments are racist."

Rep. Doug Collins of Georgia led the GOP effort to have her words stricken from the record with a rare procedural rebuke. Then Cleaver spoke, gaveled and walked off, leaving colleagues familiar with his style stunned.

"I'm watching this, my jaw dropped. I've never seen that, ever," said six-term Rep. Gerry Connolly, D-Va. "What my colleagues on the other side of the aisle have to appreciate is how hurtful, what deep wounds this resurrects, these racist words."

The shock in part was due to Cleaver's well-known emphasis on civility in an institution not known for it and at a time when social media and television are brimming with personal attacks.

"A little of the oil of civility in Congress will prevent a deluge of discord in the nation," Cleaver posted on July 26 last year.