Kavanaugh denied the story, calling it "a smear, plain and simple".
A White House spokeswoman added in a second statement that the allegation was "designed to tear down a good man".
The New Yorker published a bombshell story Sunday ahead of Kavanaugh's Thursday hearing in D.C., where he's already set to face-off against Christine Blasey Ford. who has accused him of a sexual assault when they were both in high school.
"As with any witness who comes before the Senate, the Senate Judiciary Committee can not hand over its constitutional duties to attorneys for outside witnesses", Mike Davis, Grassley's top nominations counsel, wrote in an email exchange with Ford's lawyers obtained by The Associated Press.
In addition, the New Yorker claims, some Republicans in the Senate were also informed about the new accusations. Grassley's staff also agreed to let Ford testify without Kavanaugh in the room, for there to be only one camera in the room, "adequate" breaks and a high security presence.
"The committee's majority staff learned the allegations made by Deborah Ramirez about Judge Kavanaugh from this evening's New Yorker report", said Taylor Foy, a communications director for Grassley. Perhaps the most contentious issue, though, has been a fight over who would question Ford. "You couldn't get a warrant because the three people named by Dr. Ford as having been at the party outside of Kavanaugh all say they don't know what she's talking about", he said.
A GOP Judiciary Committee investigator contacted Keyser last Tuesday, saying Keyser had been "identified" as attending that party and wanted to talk to her. Committee spokesman Taylor Foy said Keyser's name "came up" in its investigation.
It took six days of "assessing her memories" for Ramirez to say she recalled Kavanaugh committing the alleged incident, and that came only after consulting with an attorney provided by the Democrats.
Vikings Fans Stunned After 27-6 Loss
What about scoring only 6 points as a big favorite? Minnesota's running game was little help, adding just 14 yards on six carries. The Bills took the opening kickoff and marched 75 yards to take a 7-0 lead on a 10-yard run by quarterback Josh Allen .
Separately, Michael Avenatti, the lawyer best known for representing adult film star Stephanie Clifford, said on Twitter that he represents a woman "with credible information regarding Judge Kavanaugh".
Ford, meanwhile, agreed to testify Thursday after an increasingly ugly weeklong standoff that saw her forced to leave her California home as she faced death threats and the president openly attacked her credibility. California's Diane Feinstein, the committee's top Democrat, sent a letter Sunday to Republican chairman Charles Grassley urging him to refer the new allegations to the Federal Bureau of Investigation in order to ensure "a fair, independent process that will gather all the facts".
Lawyers for Ford and bipartisan representatives of the committee came to the tentative agreement after a short but productive phone call late Saturday, said a person briefed on the matter, who was not authorized to speak publicly and requested anonymity. In addition, some of us knew Debbie long after Yale, and she never described this incident until Brett's Supreme Court nomination was pending. "I will listen if she does".
A senior official at the White House said the letter amounted to "an ask to continue "negotiations" without committing to anything".
Kavanaugh has denied sexually abusing anyone at any time in his life. "We committed to moving forward with an open hearing on Thursday Sept 27 at 10:00 am". The Senate Judiciary Committee's 11 Republicans - all men - have been seeking an outside female lawyer to interrogate Ford. In an interview with The Washington Post, Blasey said a "stumbling drunk" Kavanaugh pinned her to a bed and attempted to take off her clothing before she was able to escape.
For the handful of Democratic senators running for re-election in red states, the impact of the Kavanaugh confirmation process has been unclear, with the nominee equally likely to serve as a motivating factor for voters on both the right and the left.
Republicans viewed Ford's requests as a way to delay voting on President Donald Trump's nominee. She referred to Ford as a "survivor of attempted rape" - even though Kavanaugh has denied her accusation, and every witness Ford has mentioned has contradicted her account.