Lawyers for President Donald Trump were set on Tuesday to wrap up their arguments urging acquittal in his U.S. Senate trial after making the case that explosive allegations by former national security adviser John Bolton – even if true – do not represent an impeachable offense.White House counsel Pat Cipollone departs at the end of the day as the impeachment trial of U.S. President Donald Trump continues in Washington, U.S., January 27, 2020. REUTERS/Joshua Roberts

The impeachment trial has been roiled by New York Times reporting about an unpublished book manuscript written by Bolton, who left his White House post last September. The trial will determine whether the Republican president is removed from office after being impeached by the Democratic-led House of Representatives last month on charges of abuse of power and obstruction of Congress arising from his conduct toward Ukraine.

Directly contradicting Trump’s account of events, Bolton in the manuscript said the president told him he wanted to freeze $391 million in security aid to Ukraine until Kiev helped with investigations into Democrats including Democratic political rival Joe Biden, and his son Hunter Biden, the Times reported.

Trump has said he fired Bolton. Bolton said he quit after policy disagreements.

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Trump is expected to be acquitted in the 100-seat Senate, where Republicans hold 53 seats and a two-thirds majority is needed to remove him from office under the U.S. Constitution.

GRAPHIC: Impeachment of U.S. President Donald Trump – here

Trump’s lawyers delivered about seven hours of arguments before the Senate on Monday.

Bolton’s allegations go to the heart of impeachment charges against Trump. Democrats have said Trump abused his power by using the security aid – passed by Congress to help Ukraine combat Russia-backed separatists – as leverage to get a foreign power to smear a political rival.

Alan Dershowitz, a constitutional law professor who is a member of Trump’s legal team, told the Senate on Monday: “Nothing in the Bolton revelations, even if true, would rise to the level of an abuse of power or an impeachable offense. That is clear from the history. That is clear from the language of the Constitution. You cannot turn conduct that is not impeachable into impeachable conduct simply by using words like ‘quid pro quo’ and ‘personal benefit.’”

Trump has denied telling Bolton he sought to use the Ukraine aid as leverage to get Kiev to investigate the Bidens. He has denied any quid pro quo – a Latin term meaning a favor for a favor – in his dealings with Ukraine.

Trump’s lawyers said they would continue their presentations on Tuesday. It was not clear when senators would begin submitting their questions to U.S. Chief Justice John Roberts, the next step in the trial. Roberts is presiding over the trial.

Lawyer Pat Cipollone concluded Monday’s session with Republicans’ argument that Democrats were using impeachment as a way to nullify the results of the 2016 election that Trump won. Trump is seeking re-election on Nov. 3. Biden is a leading candidate for the Democratic nomination to face Trump.

WITNESSES OR NO WITNESSES?

The Bolton disclosures prompted new calls by Democrats for Bolton and other witnesses to testify. Some moderate Republican senators, including Mitt Romney and Susan Collins, said the disclosures were likely to sway at least four Republicans to call Bolton to testify, which would give Democrats the votes necessary in the Republican-led Senate to summon him.

Senate Republicans have so far refused, however, to allow any witnesses or new evidence in the trial.

Democrats on Tuesday said the unfolding disclosures from Bolton appeared to make some Republicans uncomfortable.

“There are senators of good conscience who are wrestling with this,” Adam Schiff, who is leading the House team prosecuting the case against Trump, told MSNBC. “The question is: Will they prevail? Because if they don’t no one can call this a fair trial.”

Romney told Reuters on Tuesday that the idea of a “one-for-one” witness deal, with one witness called by Democrats and one by Republicans, “has merit,” but added: “I wouldn’t suggest any particular names.”FILE PHOTO: National Security Advisor John Bolton adjusts his glasses as U.S. President Donald Trump speaks while meeting with NATO Secretary General Jens Stoltenberg in the Oval Office at the White House in Washington, U.S., April 2, 2019. REUTERS/Joshua Roberts/File Photo

During their presentation to the Senate on Monday, Trump’s legal team turned their focus to Biden and his son Hunter Biden, who sat on the board of Ukrainian energy company Burisma while his father was U.S. vice president.

Attorney Pam Bondi defended Trump’s use of unsupported corruption allegations against the Bidens as the basis for his demand that Ukraine investigate them. That drew a rebuke from Biden campaign spokesman Andrew Bates, who dismissed Bondi’s allegations as having been widely discredited.

Ukrainian officials have said they found no indication that Hunter Biden had broken any law.

The Senate may resolve the issue of whether to call witnesses in a vote on Friday or Saturday.

While the impeachment drama has consumed Washington, it seems to have done little to alter voters’ views of Trump in at least one election battleground state. More than two dozen voters interviewed in Michigan said were most focused on jobs, healthcare and education.

“It mainly only comes up after we’re done talking about everything else,” said Larry Nearhood, a volunteer for Democratic presidential candidate Pete Buttigieg. “It’s just in the background.”

Still, most Americans want to see witnesses in the trial, according to a Reuters/Ipsos poll.