Keep your eyes on these Senate Republicans. They could upend Pete Hegseth’s confirmation.

Pete Hegseth, President-elect Donald Trump’s pick to lead the Pentagon, is on Capitol Hill Thursday to make his case with Senate Republicans as controversy continues to build around his nomination.

The Army veteran and former Fox News host will need to address allegations of sexual assault that surfaced in recent days. Concern on the Hill is only likely to build after a police report into the 2017 allegations, which Hegseth denies and wasn’t charged in, became public on Wednesday.

Four Senate Republicans would need to break ranks to sink Hegseth’s nomination. And though none has opposed him so far, many Republicans have offered a tepid defense of Trump’s pick.

Here’s a look at Republicans to watch:

Mississippi Sen. Roger Wicker: The incoming chair of the Armed Services Committee will oversee Hegseth’s confirmation process. Wicker has said he wants to be “supportive” of Hegseth and posited that his outsider status could be advantageous in shaking up the Pentagon.

While he may well back Trump’s pick, Wicker will also need to gauge the support of his committee members and their concerns as the confirmation process unfolds.

Iowa Sen. Joni Ernst: A Senate Armed Services member whose name was briefly floated for the Pentagon job, Ernst could be somewhat of a bellwether for GOP support.

Ernst has been a vocal critic of the military’s handling of sexual assault in the ranks. She was the only Republican to vote againstGen. John Hyten’s nomination for Joint Chiefs vice chair, a confirmation process that was dominated by sexual assault allegations.

Ernst has said the allegations against Hegseth merit “discussion.” She also wants Hegseth to explain his comments that women should not serve in combat jobs.

“Any time there are allegations, you want to make sure they are properly vetted, so we’ll have that discussion,” Ernst said.

The stalwarts: Many of the junior Armed Services Republicans who are closely aligned with Trump have expressed support for Hegseth: Sens. Rick Scott of Florida; Tommy Tuberville of Alabama; Markwayne Mullin of Oklahoma; Ted Budd of North Carolina; and Eric Schmitt of Missouri.

Non-Armed Services Republicans: While Thursday’s meetings likely will focus on shoring up immediate support among Armed Services members, some of the biggest wild cards could be in the wider Senate.

Sens. Susan Collins of Maine and Lisa Murkowski of Alaska most frequently bucked Trump in his first term and could be skeptical of Hegseth and other contentious picks. Sen. Todd Young of Indiana, a conservative defense hawk who declined to support Trump in 2024, has praised Trump’s initial slate, and said he’d allow Hegseth’s confirmation process to play out.

Sen. John Cornyn of Texas, the recent runner-up in the race to be the new GOP majority leader, could be an asset. Cornyn held a call with Hegseth — and on Wednesday touted him in a floor speech.

“I’ve known Pete a long time … I told him I want to be a resource for him,” Cornyn told reporters. “He came up here years ago, initially on some veterans affairs issues, and so trying to be of assistance,” Cornyn said, before downplaying the sexual assault allegation. “There’ll be plenty of time to hash that out. My understanding is it was a settlement of a dispute, and there’ll be plenty of time to flesh that out.”