President Trump’s choice of Robert F. Kennedy Jr. to be the nation’s next health secretary will face a critical test in the Senate on Tuesday, when members of the Finance Committee — including a Republican doctor uneasy about Mr. Kennedy’s views on vaccines — will vote on whether to reject the nomination or forward it to the Senate floor.
Mr. Kennedy’s fate may hinge on that doctor, Senator Bill Cassidy of Louisiana. He has said publicly that he is wrestling with how to vote, and on Monday he posted on social media what many took as a hint: a quote from the Bible on the topic of courage.
“Joshua said to them: ‘Do not be afraid; do not be discouraged. Be strong and courageous. This is what the LORD will do to all the enemies you are going to fight,’” Mr. Cassidy, who is also the chairman of the Senate Committee on Health, Education, Labor and Pensions, wrote on X.
The Finance Committee has 14 Republicans and 13 Democrats. If every Democrat votes against Mr. Kennedy, a no vote by Mr. Cassidy would deprive Mr. Kennedy of a favorable recommendation to the full Senate. But it would not necessarily doom his nomination; it is possible that Republicans could use procedural tactics to force the full Senate to vote. It is also possible that Mr. Cassidy votes to move the nomination forward on the grounds that the full Senate should consider it, while reserving the right to vote against Mr. Kennedy on the floor.
For Mr. Cassidy, voting against Mr. Kennedy would be a politically perilous step. He is up for re-election in 2026 and is already facing a primary challenge from the right.
Senator Ron Wyden of Oregon, the top Democrat on the panel, said Democrats were examining their procedural options and “trying to catalog all the different approaches” they might take, depending on how the vote goes.
On Capitol Hill on Monday, all eyes were on Mr. Cassidy, who said that he and Mr. Kennedy had a “cordial” conversation over the weekend, but was “still working through” how he would vote. During last week’s confirmation hearing before the health committee, Mr. Cassidy delivered impassioned, anguished remarks expressing his reservations about Mr. Kennedy.
“I’ve been struggling with your nomination,” Mr. Cassidy said after Mr. Kennedy repeatedly refused to disavow his past criticism of vaccines. The senator told the nominee he was worried that Mr. Kennedy would use his platform as a cabinet secretary to continue to cast doubt on vaccines and that he was too old to change.
“Does a 70-year-old man, 71-year-old man who spent decades criticizing vaccines, and who’s financially invested in finding fault with vaccines — can he change his attitudes and approach now that he’ll have the most important position influencing vaccine policy in the United States?” Mr. Cassidy asked.
“I’ve got to figure that out for my vote,” he added.
Mr. Kennedy had been under scrutiny over his decision to keep a financial stake in hundreds of vaccine cases he referred to a plaintiff law firm suing a major drug maker. After sharp questioning from lawmakers during back-to-back hearings last week, Mr. Kennedy changed course, instead declaring that he would sign over the interest in the litigation to his son, a lawyer in California. Conor Kennedy appears to be the only Kennedy son working in law at Wisner Baum, the firm that the elder Kennedy referred the cases to, claiming that Merck’s HPV vaccine, which is meant to prevent cervical cancer, caused harm.
The reversal did not quell concerns from Democrats, including Mr. Wyden and Senator Elizabeth Warren of Massachusetts.
“What is clear is that your involvement and financial interests in vaccine litigation are broad and extensive,” the senators wrote in a letter sent Sunday to Mr. Kennedy. “It seems possible that many different types of vaccine-related decisions and communications — which you would be empowered to make and influence as Secretary — could result in significant financial compensation for your family.”
Ms. Warren and Mr. Wyden asked Mr. Kennedy to pledge in writing that he would recuse himself from vaccine-related matters while he served as secretary. They also asked him to step away from vaccine-related litigation for four years after his term as secretary.
Mr. Kennedy’s rise to national prominence was fueled by his vaccine skepticism, his criticism of the pharmaceutical and agricultural industries and his embrace of organic foods. He ran for president last year, first as a Democrat and then as an independent, before endorsing Mr. Trump.
He is among Mr. Trump’s most divisive cabinet picks, and perhaps his most prominent. A scion of the storied Kennedy Democratic political clan, he has built a movement that he calls MAHA — Make America Healthy Again — and has legions of followers. Many of them are women, whom he refers to as the “MAHA Moms.”
As Mr. Cassidy said last week, “My phone blows up with people who really follow you, and there are many who trust you more than they trust their own physician.”