Senators urge managers and Trump lawyers to keep tone in check during impeachment debate

Senate Republicans on Wednesday criticized Rep. Jerry Nadler's comments at the end of a combative, 13-hour opening day of debate between House managers and President Donald Trump's legal team, arguing that the tone of the proceedings could hurt Democrats’ efforts to convince Republicans to support admitting new evidence and witnesses into the trial.

The GOP criticism came as the House impeachment managers, including Nadler, began their opening arguments in the impeachment trial on Wednesday, a presentation that could stretch over three days if Democrats use the entire 24 hours allotted to them.

"I think where House Democrats failed yesterday and maybe Senate Democrats failed, was trying to use the time in a way that would wear us out, or the chief justice out, and deny the President's response -- any response -- this week," said Sen. Roy Blunt, R-Mo., a member of Senate leadership.

During debate over Democratic amendments, Nadler, one of the House impeachment managers, accused Trump’s counsel of making false statements and restricting witness testimony - making the same arguments on the floor that House Democrats have made for weeks about Senate Republicans working with the White House on the parameters of a trial, and Republicans' refusal to agree to bringing in witnesses at the outset of proceedings.

"So far I'm sad to say I see a lot of senators voting for a cover up, voting to deny witness -- an absolutely indefensible vote, obviously a treacherous vote," Nadler said early Wednesday.

"Either you want the truth, and you must permit the witnesses, or you want a shameful cover up history will judge and so will the electorate," he said.

He also pointed out that the House Judiciary Committee invited the president's lawyers to participate in impeachment proceedings, despite the White House team's claims.

White House counsel Pat Cipollone fired back.

"The only one who should be embarrassed, Mr. Nadler, is you for the way you’ve addressed this body," Cipollone said.

Trump’s other lead impeachment attorney, Jay Sekulow, accused the House impeachment managers of trying "to shred the Constitution on the floor of the Senate."

"The Senate is not on trial," Sekulow said.

Chief Justice John Roberts scolded the House managers and the president's legal team shortly after 1 a.m. Wednesday.

"Those addressing the Senate should remember where they are," he said.

Sen. Susan Collins, R-Maine, one of the moderates who backed a single Democratic amendment on Tuesday night and is open to calling witnesses later in the trial, was spotted sending a note to the parliamentarian that raised concerns about Nadler's tone while he made his comments on the floor.

Democratic Sen. Chris Murphy of Connecticut tweeted that a Republican senator approached him, and warned that Democrats' strategy of forcing amendment votes late into the night Tuesday "might scare off" Republicans open to supporting witnesses later in the trial.

"If they're trying to win the argument that's probably not the best way to go about it," Sen. John Thune, R-S.D., told reporters.

Some Democrats appeared to acknowledge that emotions ran too high on both sides.

"I think that the chief justice’s message was heard loud and clear, and it will affect the tone going forward," said Sen. Richard Blumenthal, D-Conn., who also criticized the Trump legal team's comments.

"The Trump team had more table pounding and shouting than real facts. They channeled their inner-Trump," he said. "Their appeal was to their base. That's what ought to alienate my Republican colleagues because that's not the American people."

Speaking ahead of opening arguments on Wednesday, Rep. Adam Schiff, D-Calif, the lead House manager, said Democrats would "try to keep focused on the facts."

"The president's team would like nothing more than to provoke a bitter conflict. We're not going to let them," he said when asked about the reprimand from Roberts.

Schiff did not answer a question, initially directed to Nadler, about GOP criticism of Nadler's remarks.

ABC News' Allison Pecorin and Sarah Kolinovsky contributed to this report.