The White House and Republicans on Capitol Hill tried to distance themselves from the matter, saying they had only learned about Mr. Whelan’s theory when they began receiving questions about it from reporters. But it does bear a resemblance to a defense strategy under discussion in recent days by White House advisers and allies of the nominee in which they would accept that Dr. Blasey was assaulted but would insist the perpetrator was not by Judge Kavanaugh, who categorically denies it.
Mr. Whelan once clerked for Justice Antonin Scalia on the Supreme Court, served as a counsel to the Senate Judiciary Committee and worked with Judge Kavanaugh in the White House of President George W. Bush. He is a well-connected member of Washington’s conservative legal establishment, an informal network that exercises considerable influence over the choice and confirmation fights of judicial nominees.
Mr. Whelan did not respond to an email or phone calls seeking comment on Friday, but he told The Washington Post in a brief interview that he had not communicated with Judge Kavanaugh, the White House counsel or others at the White House “about the topic of the Twitter thread.”
Conservative operatives who have worked with Mr. Whelan raised doubts that he could have acted alone.
Steve Schmidt, an outspoken critic of the president who worked for Republicans before leaving the party, said that Mr. Whelan had been the “singularly most important and effective outside adviser involved in the confirmation effort” of two earlier Republican court nominees whom Mr. Schmidt helped lead.