WASHINGTON – As senators argue over how to conduct the impeachment trial of President Donald Trump, a majority of Americans say introducing new evidence should be allowed, according to a poll released Tuesday.

In a Monmouth University poll taken before the trial got underway, 57% of respondents say House managers should be able to present new evidence. Thirty-seven percent say they should be limited to evidence that was revealed as part of the impeachment inquiry in the House.

The support for allowing new evidence is split along partisan lines: 87% of Democrats are in favor and 24% of Republicans. Fifty-six percent of independents support allowing new evidence.

As part of a proposal by Senate Majority Leader Mitch McConnell, R-Ky., debate over whether to subpoena witnesses or request documents would come after the opening arguments and questions in the trial. Senate Minority Leader Charles Schumer, D-N.Y., said the proposal wouldn't automatically allow House Democrats to admit their evidence into the record.

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“Under this resolution, Sen. McConnell is saying he doesn’t want to hear any of the existing evidence, and he doesn’t want to hear any new evidence," Schumer said.

The question of witnesses is one of the most contentious issues in the Senate rules debate. Democrats want to call at least four witnesses, including Trump's former national security adviser, John Bolton. Some Republicans said witnesses would be unnecessary.

Last week, documents provided by Lev Parnas, an associate of Trump's lawyer Rudy Giuliani, added to the record of the alleged pressure campaign to get Ukraine to conduct investigations into Joe Biden, one of Trump's political rivals. Parnas was indicted on federal campaign finance charges.

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Americans are split on whether Trump should be removed from office after being impeached by the House of Representatives, according to the poll: 49% are in favor of removal, and 48% are opposed.

A slim majority (51%) of Americans say top Trump administration officials who refused to testify in the impeachment inquiry should be compelled to testify before the Senate. Twenty-nine percent say they should be asked, but not compelled, to testify. An additional 16% say aides should not be asked to testify at all.

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“Public opinion on allowing new evidence and compelling witness testimony in the Senate trial breaks sharply along partisan lines. But it is interesting that solid majorities in every partisan group would like to see Trump and members of his administration at least asked to appear,” Monmouth polling director Patrick Murray said.

The survey of 903 adults was conducted Jan. 16-20 and has a margin of error of plus or minus 3.3 percentage points.

Contributing: Bart Jansen