Sen. Susan Collins, R-Maine, arrives at the Capitol in Washington, Tuesday, Jan. 28, 2020. President Donald Trump's legal team prepared to wrap up arguments in his impeachment trial Tuesday as Senate Republicans wrestled with whether to allow witnesses, including John Bolton who appeared ready to contradict a key Trump claim. Credit: Manuel Balce Ceneta | AP

WASHINGTON — President Donald Trump’s legal team argued forcefully against the relevance of testimony from Trump’s former national security adviser John Bolton on Tuesday as they concluded their defense and the Senate braced for debate later this week on whether to summon Bolton and other witnesses into the impeachment trial.

“This should end now, as quickly as possible,” White House counsel Pat Cipollone declared, capping a defense presentation that painted Trump as a victim and took dismissive swipes at Bolton, the potential witness who has scrambled Republican hopes for a swift end to the trial.

A vote on witnesses, including Bolton, will likely take place on Friday after senators use the next few days to ask questions to both the House managers and the president’s defense team.

Sen. Susan Collins, R-Maine, has said that she will likely vote in favor of hearing witnesses, a position she reiterated in an interview with CBS News on Tuesday. She hasn’t specified which witnesses she hopes the Senate will call, though she said on Monday that revelations about Bolton’s potential testimony over the weekend “strengthen the case for witnesses.”

Sen. Angus King, I-Maine, told NPR on Monday that he expects between five and 10 Republican senators to support bringing in witnesses.

A day after the defense team largely brushed past Bolton, attorney Jay Sekulow addressed the controversy head-on by dismissing his manuscript — said to contradict a key defense argument about Trump’s dealings with Ukraine — as “inadmissible.” The argument was meant to preempt calls from Democrats for witnesses including Bolton, who writes in a forthcoming book that Trump told him he wanted to withhold military aid from Ukraine until it helped with investigations into Democratic rival Joe Biden.

The argument built on a separate one Monday night from Trump attorney Alan Dershowitz, who said that nothing in the manuscript — even if true — rises to the level of an impeachable offense. Sekulow also sought to undermine the credibility of Bolton’s book by noting that Attorney General William Barr has disputed comments attributed to him by Bolton.

The legal team also delved into areas that Democrats see as outside the scope of impeachment, chastising former FBI Director James Comey and seizing on surveillance errors the FBI has acknowledged making in its Russian election interference probe.

While scoffing at the manuscript, Trump and the Republicans have strongly resisted summoning Bolton to testify in person about what he saw and heard as Trump’s top national security adviser.

Senate Republicans spent two days behind closed doors discussing ideas to satisfy those who want to hear more testimony without prolonging the proceedings or jeopardizing the president’s expected acquittal.

The ideas appear to be losing steam as quickly as they emerge.

One Republican, Sen. James Lankford of Oklahoma, was floating an idea backed by Sen. Lindsey Graham of South Carolina to subpoena Bolton’s book manuscript so senators can see the evidence themselves — in private. However, Minority Leader Chuck Schumer, D-New York, called the proposal, which would keep Bolton out of public testimony, “absurd.”

“We’re not bargaining with them. We want four witnesses, and four sets of documents, then the truth will come out,” Schumer said.

Other Republicans including Sen. Pat Toomey of Pennsylvania want reciprocity — bring in Bolton or another Democratic witness in exchange for one from the GOP side. Some Republicans want to hear from the Bidens.

The case now moves toward written questions, with senators on both sides getting 16 hours to pose queries. By late in the week, they are expected to hold a vote on whether or not to hear from any witnesses.

Republicans are being warned that even if they agree to call Bolton to testify or try to access his manuscript, the White House will block him, beginning a weeks-long court battle over executive privilege and national security. That leaves the few senators, including Romney and Collins, who have expressed a desire to hear new testimony without strong backing.

Trump is charged with abusing his presidential power by asking Ukraine’s leader to help investigate Biden at the same time his administration was withholding hundreds of millions of dollars in security aid. A second charge accuses Trump of obstructing Congress in its probe.

Trump and his lawyers have argued repeatedly that Democrats are using impeachment to try to undo the results of the last presidential election and drive Trump from office.

Democrats, meanwhile, say Trump’s refusal to allow administration officials to testify only reinforces that the White House is hiding evidence. The White House has had Bolton’s manuscript for about a month, according to a letter from Bolton’s attorney.

BDN writer Jessica Piper and Associated Press writers Alan Fram, Mary Clare Jalonick, Andrew Taylor, Matthew Daly, Laurie Kellman and Padmananda Rama contributed to this report.