Trump impeachment trial live updates: Biden says charge 'not in dispute' in 1st comments on acquittal

In an 11th-hour development, the Senate has moved to call witnesses in Trump's second impeachment trial. Witnesses were not allowed at his first trial.

Five Republican senators joined Democrats on the vote Saturday brining it to 55-45.

Republican Sen. Lindsey Graham, a close ally of the former president, changed his vote after the call was read back to support witnesses, joining Republican Sens. Mitt Romney, Susan Collins, Lisa Murkowski and Ben Sasse.

The Senate moved to allow witnesses after Lead House impeachment manager Rep. Jamie Raskin, D-Md., called to subpoena Rep. Jaime Herrera Beutler, R-Wash., after she tweeted out a statement overnight reiterating details surrounding House Minority Leader Kevin McCarthy's call with Trump during the Capitol siege.

Trump's defense team slammed the notion.

In a blistering statement to reporters before the impeachment trial began on Saturday morning, Sen. Sherrod Brown, D-Ohio, called his GOP colleagues "spineless" for being poised to vote not to convict Trump out of fear he will campaign against them.

"It's so clear this president abused his power," Brown said. "It's so clear he incited violence. And my colleagues just refuse to see it because of their abject fear of Donald Trump."

"I've watched my spineless colleagues walk around with fear in their eyes for four years," Brown later continued. "And so maybe I shouldn't be surprised."

-ABC News' Benjamin Siegel

After Lead House impeachment manager Rep. Jamie Raskin, D-Md., called to subpoena Rep. Jaime Herrera Beutler, R-Wash., and Trump's defense team slammed the notion, the Senate moved to vote on calling witnesses in Trump's second impeachment trial.

In a rebuttal to the House managers requesting to subpoena GOP Rep. Jamie Herrera Beutler, R-Wash., as a witness to the impeachment trial, Trump's defense team scoffed at the idea and threatened to call 100 witnesses in response, and said the trial should wrap "today."

"They didn't put the work in that was necessary to impeach the former president," Trump's defense lawyer, Michael van der Veen argued. "But if they want to have witnesses, I'm going to need at least over 100 depositions, not just one."

"We should close this case out today," van der Veen later continued.