In the interview, Ms. Murkowski emphasized how invested she was in assessing Dr. Blasey’s story. Her view that an “arbitrary timeline” should not scuttle a potential hearing helped nudge Republicans toward reaching an agreement with the accuser’s lawyers last weekend. She canceled a meeting of the Senate committee she leads on Thursday to ensure her schedule was clear. And although she is not on the Judiciary Committee, she will be watching.
“All you can try to do is be as fair as possible to ensure that at the end of the day justice is delivered,” Ms. Murkowski said.
As senators face contradictory testimony from Judge Kavanaugh and Dr. Blasey, with little hope of independent corroboration, Ms. Murkowski is emerging as an important voice, along with Ms. Collins, Senator Jeff Flake, Republican of Arizona, and, possibly, Senator Dean Heller of Nevada, the only Republican up for re-election in November in a state won by Hillary Clinton two years ago.
As new accusations surface, their ultimate decisions looked ever more difficult. Late Monday night, a freshman roommate of Judge Kavanaugh’s at Yale, James Roche, released a statement in support of Ms. Ramirez.
“Although Brett was normally reserved, he was a notably heavy drinker, even by the standards of the time,” he wrote, adding, “he became aggressive and belligerent when he was very drunk.”
Another Yale schoolmate, Steve Kantrowitz, took to Twitter on Tuesday to contradict the assertion Judge Kavanaugh made on Fox that he was a virgin in high school and “for many years thereafter.”
“Perhaps Brett Kavanaugh was a virgin for many years after high school,” he wrote. “But he claimed otherwise in a conversation with me during our freshman year in Lawrence Hall at Yale, in the living room of my suite.”
In lashing out on Tuesday, Mr. Trump dispensed with the restraint that advisers have urged him to exercise and adopted the attack mode he prefers. He portrayed the allegations against Judge Kavanaugh as character assassination, and he challenged the credibility of Ms. Ramirez even more sharply than he did Dr. Blasey last week.
“She said she was totally inebriated and she was all messed up and she doesn’t know it was him but it might have been him,” Mr. Trump said while in New York for the annual session of the United Nations General Assembly. Then, speaking sarcastically, he added, “Oh, gee, let’s not make him a Supreme Court judge because of that.”
As the president of Colombia looked on, Mr. Trump accused the Democrats of smearing Judge Kavanaugh. “I think it’s horrible what the Democrats have done. It’s a con game they’re playing; they’re really con artists,” he said. “They’re playing a con game,” he continued, “and they play it very well. They play it actually much better than the Republicans.”
He went on to call it a con game several more times, even at one point spelling it out, “C-O-N.”
Democrats argued that Mr. Trump and other Republicans were rendering a verdict before actually hearing from any accusers. “Senate Republicans promised that ‘anyone who comes forward as Dr. Ford has deserves to be heard,’” Senate Democrats said in a statement. “Unfortunately, it appears that Republican leaders have prejudged the outcome of Thursday’s hearing.”
For many Republicans, though, the charges and countercharges have only cemented their view that Judge Kavanaugh is being smeared by a coordinated campaign of Democrats and liberal activists.
Senator Bob Corker, Republican of Tennessee, said he was not persuaded by Ms. Ramirez’s story. “I read The New Yorker article. It’s pretty thin. No one else remembered any of it,” he said. “This is really getting kind of carried away, it’s feeling more like a circus. But again, I did feel like this first accuser should be heard.”
In the interview, Ms. Murkowski was not so dismissive of the accusations. “We are at just a difficult place because the conversation is not rational on either side,” she said. She added: “Just look at some of the hateful things that are being said out there. How do you dial that back?”
“We need to be able to listen,” she said, pledging to take Dr. Blasey seriously. “We have to listen to what she will say on the record, under oath, and what Judge Kavanaugh will say on the record, under oath.”
When Dr. Blasey, a research psychologist in Northern California who also goes by her married name, Ford, came forward in an interviewthis month with The Washington Post, Ms. Murkowski and Ms. Collins had largely completed exhaustive reviews of Judge Kavanaugh’s career and legal writing, including follow-up calls with the nominee just two days before. Both senators were particularly interested in Judge Kavanaugh’s views on Roe v. Wade, the 1973 landmark decision that established a constitutional right to abortion, but privately, fellow Republicans believed the judge had probably won their support — and with it a ticket onto the court.
Those views will still influence their decisions, both senators have said. Ms. Murkowski said on Monday that Judge Kavanaugh had laid out for her a powerful case about the importance of precedent and the “reliance of interest” it creates.
“How he articulated how it had been reinforced in so many different steps, I certainly have greater confidence with the way that he portrayed to me how he views Roe,” she said.
Ms. Collins, an institutional-minded centrist who carefully reviews judicial nominees, has expressed similar views on Judge Kavanaugh and Roe and indicated that she will watch on Thursday with equal vigor.
“I had not made a decision, and obviously the hearing Thursday is an important one,” Ms. Collins told reporters on Tuesday. She expressed concern about Ms. Ramirez’s accusation and suggested that the Judiciary Committee question her under oath as well as Dr. Blasey.
Given the explosive nature of the allegations, the decision by Republicans on the Judiciary Committee to hire an outside lawyer to question Dr. Blasey was cast as a way to preserve some sense of decorum. Mindful of the backlash after sharp questioning of Anita F. Hill during confirmation hearings for Clarence Thomas in 1991, the male Republicans preferred to pass off the task to a professional and a woman.
“We have done it because we want to depoliticize the whole process, like the Democrats politicized the Anita Hill thing,” said Charles E. Grassley, Republican of Iowa and the chairman of the committee. He said he hoped to create an environment that would “not be a circus.”