President Donald Trump’s impeachment trial is hurtling toward a showdown over whether the Senate will call witnesses to testify ― namely, former national security adviser John Bolton, who has written a book manuscript that effectively confirms the quid pro quo at the heart of the impeachment charges.

Republican senators argue that calling Bolton or virtually any other witnesses would be a waste of time — because their vote won’t change. That argument is an accidental admission of the essential truth of this trial: Republicans are prepared to acquit Trump no matter what.

Sen. Pat Toomey (R-Pa.), for example, said he was “very, very skeptical” that there would be a witness who would change his mind “about how I ought to vote on the final question.”

“For the sake of argument, one could assume everything attributable to John Bolton is accurate and still the House case would fall well below the standards to remove a president from office,” Sen. Lindsey Graham (R-S.C.) said in a statement Wednesday.

Drew Angerer via Getty Images Sen. Lindsey Graham (R-SC) speaks to reporters Tuesday as he leaves a closed-door Senate Republican caucus meeting after the Senate adjourned for the day during the impeachment trial.

Graham’s colleagues have taken a similar stance. Sen. Cory Gardner (R-Colo.) said that “I do not believe we need to hear from an 18th witness,” despite Bolton’s new information. Sen. Ted Cruz (R-Texas) similarly argued that the House had already made its case and “additional witnesses are not necessary.” Sen. Jim Inhofe (R-Okla.) warned that calling witnesses would lead to a long string of people testifying and allow Democrats to “string this thing out.”

“Unless there’s a witness that’s going to change the outcome, I can’t imagine why we’d want to stretch this out for weeks and months,” Sen. Roy Blunt (R-Mo.) said earlier this week.

This is a far different stance than Graham and others took as recently as a few months ago, when they suggested that there was simply a lack of evidence to support the charges against the president.

“If you could show me that Trump actually was engaging in a quid pro quo, outside the phone call, that would be very disturbing,” Graham told Axios in October.

Trump and allies such as Graham have continuously tried to narrow the scope of the impeachment investigation and direct attention solely to the July 25 phone call between Trump and Ukrainian President Volodymyr Zelensky. Although the call alone includes Trump bringing up groundless conspiracy theories and asking Zelensky to investigate a political rival, recent months have provided additional evidence and testimony that Trump directed a quid pro quo campaign to pressure Ukraine into launching a probe of former Vice President Joe Biden and his son Hunter.

Republicans have been eager to ignore and suppress that evidence, especially when it comes to Bolton. Trump’s lawyers in the impeachment trial have argued that Bolton’s book draft is inadmissible and the White House has warned him against publishing it.

Senators are expected to debate and vote on whether to call witnesses on Friday, with Democrats needing four Republicans to side with them in order for it to pass. If witnesses are allowed, it could extend the impeachment proceedings and start a fight over who should be required to testify.

The fact that allowing witnesses would take time came up repeatedly on the Senate floor on Wednesday, as Trump’s defenders cautioned that anything but a swift acquittal could tie up the chamber indefinitely. Trump attorney Jay Sekulow said that if the Senate allows witnesses, his side would demand some as well, including the lead House impeachment manager, Rep. Adam Schiff (D-Calif.); Hunter Biden; and the whistleblower whose concerns about Trump’s phone call with the Ukrainian president brought the matter to light. Many Republicans have said they’d like to hear from Hunter Biden if witnesses are called.

Sekulow accused the House ― which was unable to obtain certain testimony and documents because the president blocked them ― of speeding through its inquiry and sending the matter to the Senate to figure out.

“Is that going to be the new norm for impeachment?” Sekulow said.

Schiff said the Trump team was trying to dissuade them from calling witnesses. He said the process would not necessarily be the slow one Trump’s attorneys warned of, because the Senate could vote to subpoena Bolton and would have Supreme Court Justice John Roberts, who is presiding over the trial, on hand to make quick decisions on whose testimony was material, whether to out the whistleblower and what part of a document was privileged. Schiff later pledged that House impeachment managers would not push back on decisions made by Roberts and challenged the defense to agree to the same. (Sekulow flatly rejected the idea: “We are not willing to do that.”)

If senators want a fair trial, they must approve witnesses, Schiff said.

“Don’t be thrown off by this claim, ‘If you even think about it, we’re going to make you pay with delays like we’ve never seen. We’re going to call witnesses that will turn this into a circus,’” Schiff told senators. “It shouldn’t be a circus; it should be a fair trial.”

Elise Foley contributed reporting.