Of the 235 voting Democrats, 118 have publicly stated their support for beginning the procedures aimed at removing Trump from office, with the symbolic threshold being crossed when congressman Ted Deutch of Florida came out in favour on Thursday.
Momentum has steadily built in the days since former special counsel Robert Mueller testified before Congress about his two-year investigation of Russian election interference and potential obstruction of justice by Trump.
Deutch became the 23rd Democratic lawmaker to support the proceedings since Mueller went before Congress and, in Deutch’s words, “confirmed the damning conclusions of his report.”
The Mueller report details how Russia interfered in “sweeping and systematic fashion” in Trump’s favour during the 2016 US presidential election campaign.
It sets out how the Trump campaign welcomed that help and repeatedly lied about it.
Democrats argue that Mueller also provided evidence for 10 instances of potential obstruction of justice by the president.
Surpassing the 50 percent threshold could be key because Pelosi has repeatedly stated her opposition to impeachment in part because the bulk of her caucus remained against launching proceedings.
Instead she prefers letting the several ongoing House investigations of Trump and his administration take their course.
In June, when Pelosi was asked whether she would support an impeachment inquiry if a majority of Democrats backed it, she declined to answer a hypothetical.
“It’s not even close in our caucus,” Pelosi said, while adding that impeachment was “not off the table.”
Pelosi has regularly noted that impeaching Trump would almost certainly lead to acquittal in the Senate, where Republicans hold a majority, and allow Trump to claim vindication and fire up his core supporters as he seeks re-election.
Some House Democrats argue that it is their constitutional duty to take action when they see evidence of presidential wrongdoing, regardless of the political ramifications.
Meanwhile congressman Will Hurd, the only African-American Republican in the House and the only Republican representing a district on the US-Mexico border, announced he will not seek re-election in 2020.
Hurd joins five other Republicans, several of them in swing districts, who announced their retirements in the last two weeks, a blow to party efforts to reclaim the House majority.