Lead House impeachment manager Rep. Adam Schiff said he doesn't think he made an unforced error during his closing arguments when he referred to an anonymous threat that the White House reportedly made to Senate Republicans to put their "head on a pike" if they voted against Trump in the impeachment trial.
Senate Republicans have vehemently denied the White House ever made such a threat.
Asked by a reporter if he botched or mishandled his closing argument by bringing up the threat, Schiff responded, "No, I don't think so."
"Look, there are going to be efforts to distract from the facts. There are going to be attacks on the managers," Schiff said during a press conference Saturday afternoon after the Senate adjourned for the weekend. "If the worst they could point to is that I referred to a published report by CBS, that's pretty thin gruel."
He said the Republicans just don't want to talk about the evidence.
"They don't want to talk about the conditioning of military aid, they don't want to talk about the solicitation of foreign interference. They just want to attack the House managers," Schiff said. "That's what you do...when your client is guilty."
He added, "I think that's all you're seeing here is that effort to distract."
"CBS News reported last night that a Trump confidant said that key senators were warned, 'Vote against the president and your head will be on a pike,'" Schiff said. "Now, I don't know if that's true."
He equated his "head on a pike' comment to how kings treated those considered traitors to their country.
Schiff said he was struck by the irony, adding "We're talking about a president who would make himself a monarch."
His comment drew immediate blowback from Republicans.
Maine Sen. Susan Collins, a key moderate Republican who could be a crucial swing vote in the impeachment fight, broke her vow of silence on the floor.
"That’s not true," Collins said several times from her seat, loudly enough to be overheard by reporters sitting in the upper level of the chamber.
She was also seen shaking her head several times in apparent frustration at the his comments.
"Not only have I never heard the ‘head on the pike’ line, but also I know of no Republican senator who has been threatened in any way by anyone in the administration," she later told reporters.
Another key potential swing vote, Sen. Lisa Murkowski of Alaska, also hit back at Schiff for his rhetoric, calling it "unnecessary."
"That’s where he lost me," Murkowski told reporters after the trial ended for the day, adding that she considered Schiff an otherwise "good orator."
"I have not been told that my head is on a pike," Murkowski added with a laugh.
Sen. John Barrasso, R-Wyo., also chimed in, saying they have never been told that.
"I don’t know if he’s making it up, but what he has proven to all of us is that he is capable of falsehoods and he would tell it to the country," Barrasso said of Schiff. "And he would tell it to us when we’re sitting in the Senate chamber, when every one of us knows it’s not true."
GOP Sen. James Lankford of Oklahoma told reporters that he considered the remark from Schiff one of the most "remarkable" moments from the House managers' final day of opening arguments.
"That is completely, totally false. And all of us were shaking our head like, 'where in the world did that story come from?' And Adam Schiff just kept saying it over and over again, as if it's true." Lankford said, adding the "whole room was visibly upset on our side of it."
He added, "to say that is insulting and demeaning to everyone. To say that we somehow live in fear and that the president has threatened all of us to put our head on a pike."
Ohio Sen. Sherrod Brown, a Democrat, acknowledged that this was the first time in several days of arguments that Republicans gave a "loud audible reaction" to the House managers’ presentation, but said he thinks it was an overreaction.
"We know the president. We know the president attacks people that work for him. We know he attacks politicians and others by name," Brown said. "We know that and we know that there is fear of him throughout the Republican caucus."
But it's unclear at this point what, if any, affect Schiff's comment will have on key Republican senators who will have to consider the question of witnesses and documents once arguments have concluded in the trial.
GOP Sen. Mike Braun of Indiana suggested on Saturday that it may push the key senators to favor Trump and his legal team's case.
"Those are the things that people that aren't paying attention to every minute of this are going to take home," Braun said. "That hurt them in a big way for anybody that might have been teetering on you know which way to go."
One of President Trump's top allies in the House -- North Carolina Rep. Mark Meadows -- said Senate Republicans have every right to be mad at Schiff.
"Republican senators have a right to not be happy with a 'head on the pike' statement," Meadows said. "I can tell you I probably get to talk to the president more than most members of Congress."
He added, "Not only is that something that he didn't say, but it's not something that he's ever used."
ABC News' Allie Pecorin, Adam Kelsey and Lissette Rodriguez contributed to this report.