"When you run for president of the United States your life is an open book and I can't imagine that Vice President Biden isn't going to have to participate in releasing all of the information related to the allegations," McConnell said. "It's a very challenging thing to run for president. And I think everyone that's done that has realized their entire life is opened up to scrutiny. And I think that's happening to Vice President Biden and they shouldn't be surprised."

Republicans have generally stuck by Trump amid sexual assault allegations leveled at him, including in 2019 when they were asked about columnist and author E. Jean Carroll's charge that Trump raped her. The president denied the allegation and claimed he never met Carroll.

Democrats are similarly sticking by Biden so far. Speaker Nancy Pelosi (D-Calif.) said on CNN Thursday that she has "great sympathy for any women who bring forth an allegation." But she also said she is "satisfied with how he has responded" to Reade's allegation.

"It's a matter that he has to deal with. But I am impressed with the people who work for him at the time saying that [they] absolutely never heard one iota of information about this. Nobody ever brought forth a claim or had anybody else tell them about such a claim," Pelosi said of Biden. "I was proud to endorse him. America needs a person like Joe Biden with his, again, his integrity and his vision for the future."

Quint Forgey contributed to this report.