Robert F. Kennedy Jr. is the latest Donald Trump Cabinet pick facing trouble in the Senate.

At least three closely watched senators are noncommittal about confirming the vaccine critic, who’s being considered to lead the Department of Health and Human Services. Those include swing votes like Sens. Susan Collins of Maine and Lisa Murkowski of Alaska, as well as Sen. Bill Cassidy of Louisiana, a physician who will chair a committee that could host confirmation hearings for Kennedy.

Kennedy can afford to lose only three Republicans during his confirmation if all Senate Democrats vote against him.

This group of senators closely resembles those who weren’t sold on former Rep. Matt Gaetz for attorney general or have questioned defense secretary pick Pete Hegseth. While Hegseth’s embattled nomination has sucked up most of the media oxygen recently, that doesn’t mean Kennedy or others will sail through the chamber smoothly.

Other nominees seem to have benefited from Gaetz’s and Hegseth’s troubles as well, flying under the radar despite potential problems. Former Rep. Tulsi Gabbard’s future as director of national intelligence could face turbulence over her past comments on Russia, among other issues. And Trump’s pick to lead the FBI, Kash Patel, has faced little to no criticism from senators so far, despite his stated intentions to clean house at the bureau.

“This is a week going after Tulsi Gabbard. Now, I guess they’re gonna skip over Kash [Patel] and then go after RFK next week, because he’s coming,” said Sen. Tommy Tuberville (R-Ala.), who said he’s meeting with Kennedy next Tuesday. Tuberville broadly supports Trump’s nominees and said Kennedy has “got a lot of great ideas” and is “outside the box.”

But Kennedy’s political baggage is another problem Republicans can’t ignore, as they try to remain largely deferential to the president-elect. Though many have boasted about party unity, some are increasingly anxious about giving a rubber stamp to nominees far outside the mainstream. But tanking more of Trump’s picks could end up sparking his ire, with Republicans bracing for him to boost primary challengers against those who won’t go along.

Unlike Gaetz and Hegseth, Kennedy has a lot of policy-centric issues, rather than mainly personal scandals. The former Democratic-turned-independent presidential candidate has a long history of vaccine skepticism and has espoused the debunked theory that vaccines have caused an increase in autism. He’s called sexual assault allegations against him “garbage” while also noting “I’m not a church boy.” And some of his proposals, like removing fluoride from American drinking water or reevaluating childhood vaccine recommendations, have drawn instant criticism from health experts.

“I realize Covid got to be pretty controversial, but vaccinations are an important part of our public health, starting with the requirement that kids get vaccinations before they go to school,” Sen. John Cornyn (R-Texas) said, noting he has questions about Kennedy’s stance on the issue.

When asked if Kennedy’s past controversies will bog down his nomination, Cassidy said everyone wants to “predict the future” but he just wants to “let things play.”

Meanwhile, Hegseth’s issues have brought another facet of the battle into sharp focus, as he insists that he will keep fighting and not withdraw. Conservative voices have mounted intense pressure campaigns against senators who aren’t openly supporting Trump picks — Sen. Joni Ernst (R-Iowa) was particularly targeted online and on TV when she withheld her support for Hegseth. She’s sounded a more positive note on the pick to lead the Pentagon this week.

Kennedy’s meetings with senators still could change his prospects — it’ll be the opportunity for questioning that many senators have been seeking. But meetings so far have proved minimally fruitful for Trump’s most controversial nominees, like Gaetz and Hegseth.

There has been speculation that Kennedy, who ran for president as a Democrat just last year before switching to an independent and later dropping out and endorsing Trump, could find salvation among Democratic senators. Many have known him or his family long before he ran for the presidency.

But a quick survey of Democrats didn’t turn up much in the way of positive comments. A handful gave deferential answers to the nomination process, saying they looked forward to meeting with him in committee and asking him questions. Sen. John Hickenlooper (D-Colo.) said he wants Kennedy to “have his chance to make his pitch.” Sen. Tim Kaine (D-Va.) similarly said he wants to talk to Kennedy directly and has “a lot of questions for him.”

Others weren’t so timid. Sen. Chris Murphy (D-Conn.), a Senate Health, Education, Labor and Pensions Committee member, said he doesn’t want a “denier of science” helming the nation’s top health agency.

“I get that there are quid-pro-quos in politics, but that one’s a pretty naked one,” Murphy said. “I know politics is crass, but that’s pretty fucking crass.”

And a GOP senator, granted anonymity to speak candidly, last week suggested Kennedy might be the next of Trump’s nominees to face problems in the Senate. They noted that goodwill from Democrats toward the nominee may even “hurt” his chances with Republicans.

Kennedy’s former party affiliation did prove a testy point with some members of the Senate GOP. Sen. Thom Tillis of North Carolina said “that’s a factor, because then you’ve got to go back and figure out what’s changed.”

“I often say about him and Tulsi [Gabbard], a few weeks ago, they were both Democrats,” Sen. Kevin Cramer (R-N.D.) said. “And so we ought to tread somewhat carefully. We’re all for recruitment, and we love people to come over. But you oftentimes don’t put a baby convert in the pulpit.”

Ben Leonard contributed to this report.