McConnell and Schumer have been unable to reach a deal on how to run the impeachment trial, squashing hopes of repeating the 100-0 vote that kicked off Clinton’s trial. McConnell needs only a bare majority to ignore Democratic demands to subpoena witnesses and documents and instead kick that decision until later in the trial.

Schumer has sought to put pressure on McConnell’s vulnerable senators by raising the question of witnesses and pointing to new emails that have been released showing the president's involvement in the Ukraine scandal.

Trump's former national security adviser John Bolton said Monday he would testify before the Senate if subpoenaed. But moderate Republicans like Lisa Murkowski and Susan Collins said they were comfortable deciding whether to call witnesses later.

Schumer and Democrats will still have some opportunities to try to shape the trial. They can force votes on their preferred trial structure, which they believe will put vulnerable Republicans in a bind.

Pelosi could deliver the articles of impeachment as soon as this week, and Republicans are eager to get moving.

“I don’t think we have any choice but to move forward," said Sen. Roy Blunt (R-Mo.), another member of the GOP leadership team. "And then the question is are the Clinton rules better than the standing rules? And I think the answer to that is yes."

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