Appearing from within the echo chamber of Fox News, Senator Lindsey Graham of South Carolina last week batted away the sexual assault and misconduct allegations dogging Pete Hegseth, President-elect Donald J. Trump’s pick to lead the Defense Department.

“I’m not going to make any decision based on an anonymous source,” Mr. Graham told Sean Hannity. “If you’re not willing to raise your hand and make the accusation, it doesn’t count.”

Some of Mr. Graham’s female colleagues had a different reaction.

“I have a lot of questions I want to ask Pete Hegseth,” said Senator Susan Collins, Republican of Maine. “Obviously, I’m concerned about the allegations against him and his treatment of women.”

Senator Joni Ernst of Iowa, a survivor of sexual assault who has positioned herself as a leader on matters of sexual assault and the military, also took the accusations seriously, before she appeared to yield this week to a pressure campaign from the far right.

“A number of our senators, they want to make sure that any allegations have been cleared, and that’s why we have to have a very thorough vetting process,” Ms. Ernst said on Fox News.

The debate over Mr. Hegseth’s fitness to be confirmed has revealed a gender divide in the Senate, where a tiny group of Republican women have emerged as some of the only skeptics.