(CNN) -- Senators have one more chance to shape the views of their undecided colleagues before they vote to decide the fate of President Donald Trump's impeachment trial — and whether witnesses like former national security adviser John Bolton will testify.
The Senate resumes its question-and-answer period on Thursday, with another eight-hour session of back-and-forth questions posed by senators to the House impeachment managers and the President's legal team. Wednesday's session gaveled out after 11 p.m. ET, more than 10 hours after it began, with more than 90 questions asked through Chief Justice John Roberts.
Many of the questions were lobbed as friendly queries — Democrats giving the managers the chance to make a point, and Republicans responding with the same tactic for the defense counsel — but there were key questions interspersed from undecided senators and to challenge the opposing side that led to illuminating and insightful — or less than insightful — responses.
The Senate is expected to vote Friday on whether to seek witnesses and documents, a vote that will decide if the trial comes to a quick acquittal or extends into an unpredictable phase where the testimony of Bolton, the Bidens and others could be sought. The votes aren't locked in yet, but GOP aides are increasingly confident they have them in hand to bring an end to the trial, potentially rapidly, after Friday's witness vote.
Two Republicans, Sens. Susan Collins and Mitt Romney, appear likely to vote for witnesses, and a third, Sen. Lisa Murkowski, may join them. Sen. Lamar Alexander of Tennessee has adopted a silent approach and hasn't tipped his hand one way or the other, but he is close to Senate Majority Leader Mitch McConnell. Beyond those four senators, Democrats are quickly running out of options, as potential GOP crossovers have declared they are voting against witnesses or signaled that's how they are leaning.
Some of the most interesting questions Wednesday came from those Republicans, though Alexander did not ask any questions. Collins and Murkowski, for instance, asked the President's team whether Trump had raised corruption and Joe Biden before the former vice president entered the 2020 presidential race. Romney asked the President's legal team when the White House first decided to hold the US assistance to Ukraine and what was the rationale the President gave then.
At the same time, Democrats struggled to answer a question from Collins in the final hour of the day Wednesday about why the House Judiciary Committee report accused the President of criminal bribery, but the articles did not. Rep. Hakeem Jeffries of New York did not answer the question directly in the initial answer, and House Intelligence Chairman Adam Schiff sought to clean it up in his final response of the night by saying that abuse of power was the larger offense, which encompassed the bribery.
Collins would not say whether the answers affected her thinking.
"I'm not going to be commenting further," she said Thursday. "I look forward to today's Q&A. I thought yesterday's Q&A was very interesting."
Alexander told CNN Thursday that he still has not made up his mind on how he will vote on witnesses. He said he is prepared to listen to the process and the rest of the question and answer session.
Democrats, meanwhile, were incensed with several answers the President's team offered. Sen. Mark Warner, the top Senate Intelligence Committee Democrat, slammed the President's team for arguing "foreign interference, in a sense, is OK if it doesn't fall into the classic definition of a campaign contribution."
And numerous Democrats criticized Harvard law professor emeritus Alan Dershowitz for arguing the President cannot be impeached for a quid quo pro if he thinks he's acting in the national interest. "If a president does something which he believes will help him get elected in the public interest, that cannot be the kind of quid pro quo that results in impeachment," Dershowitz said.
"Republicans have gone from denying what the President did, to normalizing it by claiming every President does it, to now saying there's nothing wrong with it even if he did it," Senate Minority Leader Chuck Schumer said Thursday.
Dershowitz tried to clean up the response on Twitter Thursday, saying: "They characterized my argument as if I had said that if a president believes that his re-election was in the national interest, he can do anything. I said nothing like that, as anyone who actually heard what I said can attest."
Republicans defended the President's attorney. "He makes a lot of very extreme examples to make his point," said GOP Sen. Kevin Cramer of North Dakota. "I have a tendency to do the same thing from time to time and sometimes that can be misconstrued."
While much of the focus is on the Republicans, some moderate Democrats have yet to say whether how they will vote on the overall outcome of the trial. "Am I wrestling with it? Every minute of every day," Sen. Joe Manchin, a West Virginia Democrat, said Thursday, adding he was "still in shock" over Dershowitz's comments.
Behind the scenes on Wednesday, there was a dispute on the Republican sides that could spill into public view on Thursday: Sen. Rand Paul was blocked from submitting a question that would have had Roberts reading the name of the alleged whistleblower. Roberts signaled to senators earlier this week he would not read any questions that included the alleged whistleblower's name, or significant identifying information of the alleged individual, according to sources.
Paul believes he has every right to ask his question and that Roberts has no grounds to block it, but it ran afoul of Roberts' communicated red line, and Paul was informed by GOP Senate leadership he couldn't ask it.
The debate is not over yet, however, and Paul could try to force the issue on the floor.
“Senator Paul will insist on his question being asked during today’s trial,” Paul’s spokesman Sergio Gor tweeted Thursday. “Uncertain of what will occur on the Senate floor, but American people deserve to know how this all came about.”