“Congresswoman Tlaib was elected to shake up Washington, not continue the status quo,” her office said in a statement standing by her remarks even as President Trump was denouncing them, and her, on national television.

In case it wasn’t already clear, the insurgent freshmen who promised bold and uncompromising action, uninterested in and unbowed by the strictures of the status quo, are showing no signs of wavering. They appear determined to push their party to the left, even as more experienced lawmakers fear that their antics and programs could divide the party and empower Republicans.

“I think some lessons will be learned pretty quickly around here,” Representative Dina Titus, Democrat of Nevada and a former professor of political science, said after Ms. Tlaib’s profane outburst. “You don’t want to hand the gun for the other side to shoot you with.”

The 2019 freshmen are hardly the first incoming class to come in swinging. The “Watergate babies” of 1975 came in with a mandate to clean up government. Newt Gingrich’s Republican Revolutionaries of 1995 and the Tea Party class of 2011 believed they had a mandate for conservative change; what they lacked in realism, they made up for in moxie.

This new class has deeper ideological divisions, but its liberal wing is in the spotlight, thanks to the iPhone video-Instagram generation that powered its ascent. Its reach, as of yet, has gone only so far, though. Speaker Nancy Pelosi, who took pains to welcome the freshmen and praise their victories, must also attend to the demands of more moderate lawmakers whose victories in Republican districts sealed the party’s majority — and whose re-elections are necessary to keep it.