On Tuesday, the final day of presentations from President Donald Trump's defense attorneys, the road ahead could be taking some unexpected twists and turns.

Under the approved rules, the Senate impeachment trial will enter a new phase in which senators can ask questions to the House impeachment managers and Trump's attorneys.

But the questions must be submitted to Chief Justice John Roberts in writing, and he will do the asking. Senators still have to remain silent during the trial.

• Q&A: What Can You Expect From the Senate Impeachment Trial of President Trump?

After the Q&A portion, which could last up to two days, the rules allot two hours for each side to have rebuttals.

After that, the Senate is expected to circle back to the question of whether to allow witness testimony and new evidence — something Democrats have been pushing for, and now even some Republicans appear open to the idea.

• New York Reps. Among Trump Impeachment Trial Managers

"I think neither Republicans nor Democrats want to extend this unduly. We want the truth, and we don't want to truncate the trial so we don't get the truth," Senate Minority Leader Charles Schumer of New York said at a news conference. "But we will work as expeditiously as possible to get the facts out with witnesses and documents and then we'll have a vote."

• How Donald Trump's Impeachment Inquiry Compares to Past Presidents

Allowing new witnesses and documents could be the difference between the trial lasting a few more days or a few more weeks, as the White House would certainly take the issue to court, holding up proceedings even longer.

At the end of the road: a final vote on each of the two articles of impeachment, for which 67 votes on either article is required for conviction and removal of the president, a highly unlikely prospect in the GOP-controlled chamber.

"You are being asked to remove a duly elected president of the United States, and you're being asked to do it in an election year," Trump attorney Jay Sekulow said.

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FURTHER IMPEACHMENT COVERAGE

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Impeachment Managers Make Case for Convicting Trump for Abuse of Power

Democrats Appeal for GOP to Help Convict Trump in Day 2 of Senate Impeachment Trial

Sen. Gillibrand Speaks On the Impeachment Process inside the Senate Chamber

Democrats Wrap Up Opening Arguments in Senate Impeachment Trial

Rep. Hakeem Jeffries's Star Is Rising as He Makes His Case in the Impeachment Trial