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.Jabin Botsford | The Washington Post | Getty ImagesMost Americans – including one in five 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.Some cracks in the baseBut the shifts moved in similar directions. Trump’s overall approval rating ticked down to 43% from 45% last month; among Republicans, it fell to 84% from 90%.The views of Republicans hold special importance as the House inquiry has gotten underway. Impeachment does not require GOP support in the House, but steadfast support from Trump’s party would block his conviction and removal from office in a Senate trial.The poll shows a significant chunk of Republicans have doubts.Solid majorities of Democrats and independents call the allegations that Trump sought a Biden investigation serious. While only 21% of Republicans do, another 27% say they aren’t sure.Among white women with college degrees, 55% say Congress should impeach and remove Trump from office outright, while 35% believe he should remain in office.Similarly, most Democrats and independents say Trump has not been honest about his actions on Ukraine. Just 19% of Republicans agree, while 71% do not.Trump’s weak link within the GOP is the group of Republicans who consider themselves more loyal to their party than to the president. They represent a minority of Republicans and 13% of poll respondents overall.Among those party-first Republicans, 30% call the Ukraine allegations serious and 40% say Trump has not been honest about them. On impeachment, 13% say outright that Congress should remove Trump from office while another 26% back continued investigation.Demographic dividesAmong demographic groups, Trump’s strengths and weaknesses on impeachment match the familiar contours of his standing on other matters. Age, race, gender, education and geography represent the key dividing lines.So 52% of suburbanites favor an impeachment inquiry at the least, while 52% of rural residents oppose it. Two-thirds of those under age 35 back an inquiry, while 50% of those aged 50-64 oppose it.Eight in ten African-Americans and seven in 10 Hispanics support at least an inquiry; fewer than half of whites do. Women back an inquiry by a two-to-one-margin; men are split.The combination of gender and education produces an especially broad divide. Among white women with college degrees, 55% say Congress should impeach and remove Trump from office outright, while 35% believe he should remain in office.White men without college degrees – consistently Trump’s strongest group – say the opposite. Just 28% want his term foreshortened, while 68% want him left to complete it.The Biden factorAmong question that has hovered over the Ukraine scandal is whether it would damage former Vice President Biden. Trump has said the investigation he seeks would explore whether Biden took official action to benefit a Ukrainian energy firm in which his son Hunter Biden had taken a role.No evidence has emerged that the vice president did so. And there’s no evidence in the NBC/WSJ poll that Biden’s standing has suffered.Americans’ feelings toward Biden – 33% positive, 34% negative – are unchanged from the 34%/38% the poll recorded in August. Among Republicans, assessments of Biden actually improved a little to 18%/57% from 11%/67% in August.