- As a clip of Michigan Democrat Rashida Tlaib's animated comments circulated widely on social media, President Trump tartly dismissed the threat of impeachment.
- Newly elected Democratic House Speaker Nancy Pelosi appeared loath to reign in the congresswoman's language.
- As a long-time Trump critic, Tlaib made calls for his impeachment central to her campaign -- and was once arrested for heckling the then-candidate during his White House run.
- House Democrat Brad Sherman on Thursday formally introduced impeachment measures against Trump. They are unlikely to get a vote on the House floor, at least for now.
A Democratic congresswoman kicked off her term with an expletive-laced vow to impeach Donald Trump, testing her party's discipline and earning a chiding Friday from the president.
As a clip of Michigan Democrat Rashida Tlaib's animated comments circulated widely on social media, President Trump tartly dismissed the threat of impeachment, while the newly elected Democratic House Speaker Nancy Pelosi appeared loath to reign in the congresswoman's language.
"How do you impeach a president who has won perhaps the greatest election of all time?" Mr Trump said on Twitter, saying Democrats only consider impeachment "because they know they can't win in 2020."
At an event hours after her swearing-in on Thursday, Ms Tlaib told supporters that "we are gonna go in there and we're gonna impeach the motherfucker."
The crowd roared, and he hugged supporters.
Salty language by US lawmakers -- or presidents, for that matter -- is nothing new. Mr Trump, hardly the paradigm of verbal decency, last year derided African nations as "shithole" countries, after all.
But when Mr Trump was asked about his critic's comments, he said they were "disgraceful," and "highly disrespectful to the United States of America."
"I think she dishonoured herself and I think she dishonoured her family, using language like that," he added.
The timing and optics of Ms Tlaib's outburst are notable.
Democrats have just won control of the House of Representatives, after eight years in the minority. Ms Tlaib, 42, is one in a cadre of ebullient, media-savvy rising stars -- the self-described "radical" Alexandria Ocasio-Cortez is another -- who aim to shake up Washington's status quo.
Such progressives will be eager to push back against an administration they believe has abused its authority in the nearly two years since Trump's inauguration.
Doubling down on her outburst, Ms Tlaib -- the first Palestinian-American elected to Congress -- tweeted Friday: "I will always speak truth to power. #unapologeticallyMe."
But she dodged reporters repeatedly asking about her remarks.
Ms Tlaib found support on Twitter, where #ImpeachTheMF was a trending item in the United States on Friday night, with more than 110,000 tweets.