National surveys have been less consistent about the issue of removal. A few high-profile national surveys, including a Fox News poll criticized by the president, show a majority of voters support impeachment and removal. But many surveys have not shown support for removal.

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An NBC/WSJ poll, for instance, found that adults opposed impeachment and removal by a six-point margin, 49 percent to 43 percent, nearly the reverse of Fox’s result of 51 percent supporting and 43 percent opposed . Other surveys — from Marist College, Quinnipiac, CNN/SSRS and Monmouth College — also found more opposition than support for impeachment and removal. The Times/Siena results are fairly consistent with those surveys.

A group that could be crucial to shifting the balance of public opinion is voters who say they support the inquiry but are not ready to support removing the president. This 7 percent slice of respondents tends to be younger — 33 percent are 18 to 34 — and nearly half are self-identified independents. They could prove tough for Democrats to convince: 51 percent say that the president’s conduct is typical of most politicians, perhaps suggesting that they hold a jaded view of politics that would tend to minimize the seriousness of the allegations against him.

Mr. Trump’s supporters from 2016 are nearly unanimous in their opposition to removing him. Over all, 94 percent of respondents who said they voted for him four years ago said they opposed his impeachment and removal. It is possible that Trump voters who have soured on him are less likely to divulge their 2016 preference to a pollster. (Crosstabs available here.)

Trump voters are not convinced that the president’s conduct was atypical for politicians in Washington. Only 11 percent of Mr. Trump’s 2016 supporters believe that his Ukraine-related conduct is worse than the conduct of most politicians, while 75 percent said it was typical.

Democrats and self-reported Hillary Clinton voters strongly support impeachment and removal, but they are divided by ideology and levels of political engagement.

Over all, 83 percent of Democrats and 85 percent of Mrs. Clinton’s voters said they supported impeachment and removal from office, compared with 93 percent of Republica ns who opposed.