House Democrats and defense lawyers made final arguments Thursday for more than nine hours on the eve of Friday's crucial vote on additional evidence and witnesses.
Officially structured as the second day of the question-and-answer portion of the trial, the tenor and content of the questions directed to both the president's lawyers and the Democratic House managers grew increasingly partisan and rhetorical as the day wore on.
At least one question was incendiary enough to be rejected outright from the presiding officer, Chief Justice of the Supreme Court John Roberts, and reporters watching from the Senate gallery noted an increased number of senators away from their seats.
Yet the most important questions on Capitol Hill on Thursday were not the ones being read by Roberts himself. They were the ones swirling around a small group of moderate Republican senators who are still undecided on whether to vote for additional witnesses and documents in the trial.
Late Thursday night, two of those senators, Lamar Alexander of Tennessee and Susan Collins of Maine, announced their plans.
Alexander confirmed that he would vote against any proposals for further witnesses. Collins broke the other way, announcing that she will vote to admit additional evidence in the trial.
The witness vote is expected to occur Friday afternoon, and will be a pivotal moment in the impeachment proceedings that have dogged Trump for months.
On Wednesday, Sen. Mitt Romney, R-Utah, signaled that he would vote with the Democrats. With Collins and Romney both yesses, and Alexander a no, it remained unclear late Thursday whether Democrats would be able to convince the minimum of four GOP senators required to admit new witnesses and documents.
The House voted to impeach Trump last month on articles of abuse of power and obstruction of Congress. Democrats accuse Trump of withholding congressionally appropriated military aid to Ukraine while pressuring the country to announce probes into former Vice President Joe Biden and his son, as well as a debunked conspiracy theory about 2016 election interference.
On balance, Alexander's no vote may have dealt a mortal blow to Democrats' hopes of calling additional witnesses in Trump's trial.
Chief among these witnesses is former National Security Advisor John Bolton, who writes in a forthcoming book that Trump told him last summer that he didn't intend to release the U.S. aid to Ukraine until the Ukrainians agreed to investigate Trump's political rivals.
It's highly unlikely that two-thirds of the Senate will vote to throw a Republican president out of office.
Here are the top moments from the impeachment trial Thursday:
For the first time, Chief Justice of the Supreme Court John Roberts rejected one of the questions that a senator posed to the legal teams.
Senators are ordered to remain silent throughout the trial; their questions for the legal teams were submitted in writing to Roberts, who read them aloud in the chamber.
On the first day of questioning on Wednesday, Roberts read every question that senators posed. But on Thursday, he rejected the first question submitted by a Republican senator, Kentucky's Rand Paul.
"The presiding officer declines to read the question as submitted," Roberts announced.
Paul's question included the name of a federal official who has been alleged to be the anonymous whistleblower whose bombshell complaint about Trump's July 25 call with Ukraine President Volodymyr Zelenskiy spurred Democrats to support an impeachment inquiry.
Immediately after Roberts refused to read the question, Paul held a press conference outside the Senate chamber.
With only a few Republicans publicly willing to even consider voting for more witnesses, Democrats have a razor-thin margin for error.
Schiff, in an appeal to Republican senators, proposed limiting additional depositions in the trial to just one week.
"I will make an offer to opposing counsel, who have said that this will stretch on indefinitely if you decide to have a single witness," the California representative said. "Let's cabin the depositions to one week."
Republicans hold a 53-47 majority in the Senate, meaning at least four GOP senators will have to break with their party and vote for a resolution to admit additional witnesses and documents into the trial. So far only Romney, a rare Republican critic of Trump, and Collins have said they plan to side with Democrats in the vote.
Trump's defense lawyers and his allies in Congress have griped about the impeachment trial dragging on if the Senate allows new witnesses. Senate Majority Leader Mitch McConnell, R-Ky., has been adamant about finishing the trial as soon as possible.
Jay Sekulow, one of Trump's defenders in the Senate trial, scoffed at Democratic senators when asked if he knew who is paying Rudy Giuliani, the president's personal lawyer.
Giuliani, who was conducting a shadow foreign policy campaign to get Ukraine to announce the investigations sought by Trump, has previously said that Trump is not paying him for legal fees and international travel.
Neither Schiff nor Sekulow answered the question about who is paying Giuliani. Schiff said he doesn't know and Sekulow in his response didn't address it.
Instead, Sekulow railed against the question, saying it's absurd to be concerned about who's paying Giuliani and the senators should focus on Biden's son's involvement in Burisma, a Ukraine natural gas company on which Hunter sat on the board.
"When the vice president of the United States was charged by the then president of the United States with developing policies to avoid and assist in removing corruption from Ukraine and his son was on the board of a company that was under investigation for Ukraine and you're concerned about what Rudy Giuliani, the president's lawyer, was doing?" Sekulow said.
"When he was over trying to determine what was going on in Ukraine?"
Schiff said Giuliani's dealings raise "profound questions, questions that we can't answer at this point."
"I don't know who's directly paying the freight for it," Schiff said, "but I can tell you the whole country is paying the freight for it because there are leaders around the world who are watching this and they're saying the American presidency is open for business."