Senate Majority Leader Mitch McConnell (R-KY) is ready to begin the Senate’s impeachment trial without an agreement with Democrats on witnesses, according to a report.

Politico reports: McConnell has locked down sufficient backing in his 53-member caucus to pass a blueprint for the trial that leaves the question of seeking witnesses and documents until after opening arguments are made, according to multiple senators. That framework would mirror the contours of President Bill Clinton’s trial and ignore Senate Minority Leader Chuck Schumer’s demands for witnesses and new evidence at the outset. No final decision has been made to move forward with a partisan approach, but in a brief interview, McConnell said he would address the possibility of spurning Democrats on Tuesday afternoon. He’s already won key backing from the handful of Republican swing votes heading into the trial. On Monday, moderates senators Susan Collins (R-ME) and Lisa Murkowski (R-AK) voiced support for McConnell’s strategy, stating the trial should call additional witnesses later in the process, akin to then-President Bill Clinton’s trial in 1999. “The process moved to a period during which the Senate debated and voted that three witnesses should be deposed. I believe that this process — the Clinton approach — worked well,” Collins told reporters. Murkowski said: “I think we need to do what they did the last time they did this unfortunate process and that was to go through a first phase and then they reassessed after that.”

The development comes as McConnell and Schumer remain at an impasse over the Senate minority leader’s demand to allow four current and former White House officials to testify at the trial. John Bolton, former White House national security advisor, said Monday that he will testify if subpoenaed.

“The House has concluded its Constitutional responsibility by adopting Articles of Impeachment related to the Ukraine matter. It now falls to the Senate to fulfill its Constitutional obligation to try impeachments, and it does not appear possible that a final judicial resolution of the still-unanswered Constitutional questions can be obtained before the Senate acts,” Bolton said in a statement. “Accordingly, since my testimony is once again at issue, I have had to resolve the serious competing issues as best I could, based on careful consideration and study. I have concluded that, if the Senate issues a subpoena for my testimony, I am prepared to testify.”

Bolton’s willingness to testify places additional pressure on House Speaker Nancy Pelosi (D-CA), who has delayed transferring two articles of impeachment to the Senate, claiming Schumer’s proposed witnesses need to be heard to ensure a “fair” trial.

In a recent floor speech, McConnell slammed Pelosi’s demand as a “non-starter” and a “fantasy.”

Nonetheless, Senate Minority Leader Chuck Schumer (D-NY) pledged Tuesday to force votes for witnesses at the beginning of the trial, even though Republicans have the votes to block the demand.

“Make no mistake, on the question of witnesses and documents, Republicans may run but they can’t hide. There will be votes at the beginning on whether to call the four witnesses we’ve proposed and subpoena the documents we’ve identified,” said Schumer. “If every Republican senator votes for a rigged trial that hides the truth, the American people will see that the Republican Senate is part of a large and awful cover-up.”