President Donald J. Trump stops to talk to reporters and members of the media as he walks from the Oval Office to board Marine One on the South Lawn of the White House on Thursday, Sept 12, 2019 in Washington, DC.

Most Americans — including 1 in 5 Republicans — now back an impeachment inquiry or already believe Congress should remove President Donald Trump from office, a new NBC News/Wall Street Journal poll shows.

The survey shows how public sentiment has moved amid the unfolding scandal over Trump's request that Ukraine investigate his potential 2020 rival Joe Biden. The share of Americans who say Congress should let Trump complete his term has dipped to 39%, from 50% in July.

At the same time, the proportion who say Congress should move to impeachment and removal has ticked up to 24% from 21%, while those who support an impeachment inquiry have swelled to 31% from 27%. Taken together, that 55% majority backing an impeachment inquiry at minimum is the highest the NBC/WSJ poll has shown this year.

That represents a gradual, not dramatic, shift in opinion. But it shows that, after the political hazards of the Trump-Russia investigation appeared to dissipate during the summer, the president faces new and potentially more-threatening trouble over Ukraine.

"What we're seeing in this poll is an openness and willingness to listen to new information," said Republican pollster Bill McInturff. His Democratic counterpart Peter Hart added, "There's not a scintilla of good news for Donald Trump in this survey."

A different question asked survey respondents to look beyond the investigation and assess the ultimate action Congress should take. By that measure, 43% of Americans say Trump should be impeached and removed from the presidency, while 49% say he should remain in office.

The telephone poll of 800 American adults was conducted Oct. 4-6 following last week's release of a partial transcript of Trump's July 25 call with Ukraine's president and text messages by his diplomats. Some shifts fall within the survey's 3.87 percentage-point margin for error.