The Senate barreled on Friday toward a late-night vote on whether to confirm Pete Hegseth as secretary of defense, with the outcome still uncertain as a handful of Republicans weighed whether to back President Trump’s pick to lead the Pentagon.
Mr. Hegseth’s confirmation was further complicated earlier this week, when a former sister-in-law submitted a sworn statement to the Armed Services Committee accusing him of having been “abusive” toward his second wife and frequently intoxicated in public and private, including at least once while in uniform.
Mr. Hegseth denied the allegations in the affidavit, as he had denied an earlier allegation of sexual assault, as well as accusations of financial mismanagement and public intoxication. But the document has forced undecided Republicans to grapple anew with whether Mr. Hegseth has the character and comportment to manage an active-duty military of about 1.3 million service members and a Pentagon budget of nearly $850 billion.
Two Republican senators — Susan Collins of Maine and Lisa Murkowski of Alaska — have already publicly announced they intend to oppose Mr. Hegseth’s confirmation. If one more Republican were to join them, Vice President JD Vance could cast a tiebreaking vote to ensure his approval. But if more broke ranks, it would sink Mr. Hegseth’s bid.
In comments to reporters at the White House on Friday, Mr. Trump suggested he was bracing for at least one more Republican to potentially oppose Mr. Hegseth’s confirmation.
“I was very surprised that Collins and Murkowski would do that,” he said on the South Lawn as he departed for a trip to North Carolina and California. “And of course Mitch is always a ‘no’ vote I guess.”
“Is Mitch a ‘no’ vote?” he added. “How about Mitch?”
Mr. Trump was referring to Senator Mitch McConnell, Republican of Kentucky, who has been notably silent on Mr. Hegseth’s nomination. Mr. McConnell voted on Thursday to move ahead with the confirmation vote. Senator Thom Tillis, Republican of North Carolina, also voted to proceed to a final vote, though he told reporters he was still doing “due diligence” on the nomination.
Most Republicans have dismissed the affidavit of the former sister-in-law, Danielle Diettrich Hegseth, pointing to a statement that Mr. Hegseth’s ex-wife Samantha Hegseth gave to NBC News denying that Mr. Hegseth ever physically abused her to discredit all the claims.
Senator Joni Ernst, Republican of Iowa, who had wrestled with whether to support Mr. Hegseth for weeks until endorsing under pressure, told reporters that Samantha Hegseth’s denial of physical abuse meant the affidavit “carries no weight.”
Samantha Hegseth is under the constraints of a non-disparagement clause in the couple’s 2018 divorce settlement. In that decree, Samantha and Pete Hegseth agreed to “refrain from engaging themselves in any public discourse, including through either traditional media or social media, disparaging the other party and will take reasonable steps to encourage friends and family to refrain from doing so.”
Such clauses are a common feature of divorces that involve children, as the Hegseths’ did.
In a recent interview with F.B.I. investigators, Samantha Hegseth said that Mr. Hegseth had drunk to excess and continued to do so, according to a person with knowledge of the findings.
The F.B.I. did not comment.
Should the Senate reject Mr. Hegseth’s nomination, it would be the first time since former President George H.W. Bush’s administration that a defense secretary nominee has failed on a confirmation vote. In 1989, the Senate rejected John Tower, Mr. Bush’s pick for defense secretary, by a vote of 47 to 53, over concerns about his drinking, his conduct toward women and potential conflicts of interest because of his work for defense contractors.
If Mr. Hegseth is confirmed, it is likely to be by the closest margin in modern times for a secretary of defense.
