With his election victory on Nov. 5, Trump has largely solidified his hold over the Republican Party. However, some Republicans in the Senate have remained stubborn, signaling they may not support Trump’s Cabinet picks, particularly former Rep. Matt Gaetz for attorney general and Pete Hegseth for defense secretary.

Here are the four Republican Senators who may prove to be thorns in Trump’s side:

Thom Tillis

Sen. Thom Tillis (R-NC), residing in a swing state known for its preference for Democrats in non-presidential races, faces a tough reelection in 2026. Conscious of this, he is sure to be hesitant in rubber stamping Trump’s more controversial Cabinet picks.

“I will consider Matt Gaetz like I will anyone else, but if they don’t do the homework, don’t be surprised if they fail. Maybe they’ve already done that work,” he told reporters after Gaetz’s nomination. “Nothing surprises me in politics, nothing. And I’m okay with this. But at the end of the day we have a process, and we’ll just have to run through it.”

Tillis said that he would keep an open mind and that his main priority in deciding is “a defensible résumé, and a really clean vetting. Produce that he’s got a chance, don’t, and he doesn’t.”

Tillis said on Monday that he had received a call from Gaetz.

Lisa Murkowski

Sen. Lisa Murkowski (R-AK), a centrist Republican, is known for not being on the same wavelength as Trump. She has signaled that she will not be voting to approve Gaetz, not seeing him as a serious candidate.

“I don’t think it’s a serious nomination for the attorney general,” she said. “We need to have a serious attorney general. And I’m looking forward to the opportunity to consider somebody that is serious. This one was not on my bingo card.”

Murkowski had a similar reaction to the nomination of Hegseth.

“Wow,” she said. “I’m just surprised, because the names that I’ve heard for secretary of defense have not included him.”

Mitch McConnell

Though stepping down as Senate Republican leader, Sen. Mitch McConnell (R-KY) isn’t retiring from his long-held seat. While he has publicly supported Trump during the 2024 race, a recent book revealed the personal animus he privately expressed toward him, especially after the Jan. 6 riot.

McConnell said after the riot that “it’s not just the Democrats who are counting the days” until Trump left office and that his behavior “only underscores the good judgment of the American people. They’ve had just enough of the misrepresentations, the outright lies almost on a daily basis, and they fired him.”

“And for a narcissist like him, that’s been really hard to take, and so his behavior since the election has been even worse, by far, than it was before because he has no filter now at all,” McConnell added.

It remains to be seen whether this personal animus will carry into objecting to Trump’s Cabinet picks. For his part, McConnell said, “we are all on the same team now.”

Susan Collins

Sen. Susan Collins (R-ME) has a rocky relationship with the president-elect, being one of the few Republicans to vote to impeach him after the Jan. 6 riot. While she voiced skepticism about Gaetz, she didn’t commit to supporting or opposing his nomination.

“He’s under investigation by the House Committee on Ethics. Obviously, the president has the right to nominate whomever he wishes, but this is why the background checks that are done by the FBI and the advice and consent process in the Senate, and public hearings are also important,” she said.