"If the trial is rigged to keep hidden the most damning, most important, most relevant evidence, then it's not a trial. Nor is it an acquittal. It's a cover-up."
Senate Minority Leader Chuck Schumer on Friday accused the Republican Party of orchestrating the "greatest cover-up since Watergate" as the Senate prepared to debate and vote on whether to allow witnesses to testify in President Donald Trump's impeachment trial.
"This is much bigger than President Trump. Preventing witnesses, evidence, and transparency in President Trump's impeachment trial potentially undermines the Constitution for generations."
—Karen Hobert Flynn, Common Cause
The Senate is widely expected as early as Friday evening to oppose permitting witnesses, given swing vote Sen. Lamar Alexander's (R-Tenn.) announcement late Thursday that he will vote no. Alexander's decision sparked widespread anger and the trending Twitter hashtag #LamarAlexanderIsACoward.
Schumer said during a press conference Friday that if the Senate votes against allowing witnesses, "the president's acquittal will be meaningless."
"This is about truth, and today the Senate will vote on whether witnesses and documents are allowed in this trial," said Schumer. "The importance of this vote is self-evident."
The Senate at 1pm ET is scheduled to begin four hours of debate on whether to approve witnesses, followed by a vote. If the Republican-controlled chamber decides against allowing witnesses, it will be the first time in U.S. history the Senate has held an impeachment trial without witness testimony, according toPolitiFact.
A final vote on whether to acquit or remove Trump could come as early as Friday evening, but anonymous Republican senators and aides toldPolitico the trial could extend until next week if House Democratic impeachment managers push for more time to make closing arguments.
Just ahead of the Senate debate on witnesses, the New York Timesreported that former national security adviser John Bolton—one of the potential witnesses in the trial—alleges in an unpublished book manuscript that Trump instructed him in May of 2019 to help with the "pressure campaign to extract damaging information on Democrats from Ukrainian officials."
Sen. Chris Murphy (D-Conn.) tweeted Thursday night that the Senate will be "disgraced" if it votes to acquit Trump without hearing witness testimony or considering documentary evidence that the White House has withheld from Congress.
"If the trial is rigged to keep hidden the most damning, most important, most relevant evidence, then it's not a trial," wrote Murphy. "Nor is it an acquittal. It's a cover-up."
Sen. Elizabeth Warren (D-Mass.), a 2020 Democratic presidential candidate, wrote in a pair of tweets Friday morning that "history will judge us for what happens next."
"Faith in our American institutions is at an all-time low," said Warren. "The fact that GOP senators are covering up the president's corruption with a sham impeachment trial without witnesses documents doesn't help."
Karen Hobert Flynn, president of government watchdog group Common Cause, warned in a letter (pdf) sent to every U.S. senator Thursday that ending the trial without witnesses "could undermine our democracy for generations."
"This is much bigger than President Trump," Hobert Flynn wrote. "Preventing witnesses, evidence, and transparency in President Trump's impeachment trial potentially undermines the Constitution for generations."
"Americans deserve nothing less than the full truth," she added. "They deserve to see a fair trial, and they are watching closely to see if Senate Republicans fulfill their constitutional duty to serve as an impartial jury or blindly conduct a rigged trial."