Support for removing President Trump from office has leapt since Speaker Nancy Pelosi opened an impeachment inquiry against him, but his Republican backers appear to represent an increasingly loyal minority, according to polls released this week.
As support for impeachment grows, the president’s base is digging in its heels. But he remains disliked and mistrusted by most of the country, suggesting that Democrats could find sufficiently broad support for impeachment without converting many Republican voters.
A majority of registered voters now approve of the House’s inquiry into impeaching the president, a poll released on Monday by Quinnipiac University showed. A Monmouth University poll of all Americans released on Tuesday, meanwhile, found that 49 percent support the inquiry — just shy of a majority, but still an eight-point jump from August.
Back-to-back Quinnipiac polls in late September — one conducted in the days leading up to Ms. Pelosi’s announcement last week, then another taken just afterward — showed that support for Mr. Trump’s ultimate removal from office jumped 10 points after the House opened its inquiry. This was driven by a surge among Democrats and a gentler uptick from independent voters.
Voters are now evenly divided on whether Mr. Trump should be removed, with 47 percent saying he should be and the same number saying he should not, according to the latest Quinnipiac survey. Last week 37 percent of voters said he should be, and 57 percent said he should not. (The Quinnipiac polls surveyed only registered voters; most other recent polls have included all American adults.)
Even as Democrats and independents become more supportive of impeachment, there are signs that Ms. Pelosi may have a hard time building nationwide consensus.
The share of Republican voters expressing strong approval for Mr. Trump’s job performance rose by 12 points since last week, from two-thirds to nearly four in five, according to the Quinnipiac polls. And the share of Republican voters saying Mr. Trump is generally an “honest” person has spiked since March, when Quinnipiac last asked the question: from 66 percent then to 83 percent today.
This suggests that the Republican base’s support for the president might be hardening as he comes under increasingly serious fire — even with evidence mounting that Mr. Trump pressured Ukraine’s president, Volodymyr Zelensky, to investigate the son of a political rival, former Vice President Joseph R. Biden Jr.
“The number of Republicans who say they approve strongly has risen since last week,” Mary Snow, a polling analyst at Quinnipiac, said in an interview. “So there is a real partisan divide to these questions.”
The percentage of voters saying they think the president “believes he is above the law” also remains stuck exactly where it was in early May: at 56 percent, according to the latest Quinnipiac poll. Just 15 percent of Republican voters hold that view of him.
Independents are split on whether the president should be impeached and removed, but they generally express support for the House’s inquiry. According to a CNN poll of all Americans taken after Ms. Pelosi’s announcement, support among independents for Mr. Trump’s eventual removal is now 11 points higher than it was in May. It stands at 46 percent, roughly even with the 45 percent of independents who say he should be allowed to remain in office.
That number appears poised to move in one direction or the other. When asked in a CBS News poll released on Sunday whether it was too soon to say if Mr. Trump should be impeached over the Ukraine scandal, roughly a quarter of independents said it was.
In the Monmouth poll, respondents were asked how much they had heard about reports that Trump had asked Mr. Zelensky to investigate Mr. Biden’s son; 27 percent said they had heard only “a little,” and another 21 percent said they had heard nothing at all about it.
Whit Ayres, a Republican pollster, said that given the steadiness of Mr. Trump’s approval rating throughout his term in office, it seems unlikely to drop significantly during the inquiry. But that approval rating has generally remained at just over 40 percent, suggesting that a decisive majority could end up supporting impeachment anyway, Mr. Ayres said.
“The group to watch over the next few months is the 15 or so percent of the American electorate that disapproves of Donald Trump’s job performance, but until the Ukrainian news has opposed impeachment,” he said. “If that 15 percent that oppose Donald Trump moves to support impeachment, then you’ll have between 55 and 60 percent of the country supporting impeachment and removal from office. That becomes a significant development.”