Health Secretary Robert F. Kennedy Jr. on Wednesday will face the two Republican lawmakers historically willing to criticize him: Sens. Bill Cassidy and John Barrasso.

Yet it’s unclear whether the two senators – both doctors – will be willing to pick a fight with President Donald Trump’s health secretary ahead of the midterm elections.

Kennedy is scheduled to appear before the Senate Finance Committee and the Health, Education, Labor and Pensions Committee; it is senators’ first shot in more than seven months to publicly question Kennedy over his controversial actions to roll back vaccine recommendations, bypass his hand-selected panel of vaccine advisors and revise a federal website to suggest autism might be linked to infant vaccines.

Cassidy, a Louisiana gastroenterologist who chairs the Senate HELP committee, has been Kennedy’s harshest critic on vaccine policy. Earlier this year, Cassidy wrote on X that the Centers for Disease Control and Prevention’s decision to cut the number of recommended childhood vaccines from 17 to 11 will “make America sicker.” Tensions escalated dramatically between the two in November, when Kennedy scorned his promises to Cassidy not to remove assertions on federal websites denying a link between vaccines and autism.

But Cassidy has recently signaled he’s focusing on the top voter concern of affordability, holding a hearing last week on lowering drug prices and announcing a policy package aimed at giving insurance subsidies directly to people and making prices more transparent.

He is facing a primary challenger next month who is backed by allies of the administration’s Make America Healthy Again movement. Barrasso, a Wyoming orthopedic surgeon who told Kennedy last year his policies made Americans more vulnerable to measles and hepatitis B, is also up for reelection this year in a deep red state.

A slate of other issues more appealing to the party’s conservative base — abortion, family planning funding — as well as issues with broad appeal like drug prices and health affordability, could feature heavily in Republicans’ questioning of Kennedy.

Kennedy will almost certainly face more sharp questions from Democrats, who see him as a fundamental threat to the nation’s public health system.

Sen. Ron Wyden, the top Democrat on the Finance Committee, plans to press Kennedy on allegations by journalist Olivia Nuzzi – who wrote about an affair with Kennedy in her 2025 book “American Canto” – that he used a psychedelic known to induce near-death experiences.

“Someone in this position engaging in illegal drug use demonstrates a severe lack of sound judgment,” Wyden wrote in a letter to Kennedy ahead of the hearing.

Sen. Angela Alsobrooks, the junior senator from Maryland who has led calls for Kennedy’s resignation and clashed with him in previous hearings, told NOTUS that Democrats “have to really be on our toes to make sure we are holding him accountable.”

Alsobrooks said she doesn’t see a way for Democrats to collaborate with Kennedy, even on issues where they may overlap with the MAHA movement, because the health secretary is “not trustworthy.”

“He’s absolutely a person whose credibility has been shot,” Alsobrooks said. “Those issues are important, of course — healthy foods and all that. But he’s certainly not the representative.”

Alsobrooks added that she would have doubts about voting for any nominee for a health leadership position in the Trump administration, regardless of their scientific credentials,. “They have largely selected people not on the basis of their credentials, but on the basis of whether or not they would rubber stamp this president’s agenda,” she said.

Testifying Tuesday before a House Energy and Commerce subcommittee, Kennedy refused to commit to accepting any vaccine recommendations made by Erica Schwartz, the White House’s new CDC nominee who has been largely endorsed by the public health establishment.

“I’m not going to make that kind of commitment,” Kennedy said in response to a question from Rep. Raul Ruiz, a California Democrat.

Criticism from Republicans has been sparse: Only one Republican directly confronted Kennedy on an issue during hearings in the House last week. Blake Moore, a Utah representative on the House Ways and Means Committee, told Kennedy he was “underwhelmed” by Trump’s September statement linking Tylenol use during pregnancy to autism.

“My wife was hurt,” said Moore, whose son is on the autism spectrum.

Kennedy appeared to be trying to stay on message during his previous hearings, but at times appeared on shaky footing when questions about hot-button topics — like spiking costs on the Affordable Care Act marketplaces that cover about 23 million Americans.

He told Texas Democratic Rep. Greg Casar last week that “almost all” of the 1.5 million people who have dropped off this year are illegal immigrants — even though his own subordinates have acknowledged it’s because of spiking premium costs after congressional Republicans didn’t extend extra, COVID-era subsidies.

“I don’t know about … undocumented immigrants,” Centers for Medicare & Medicaid Services Administrator Mehmet Oz told NOTUS on Tuesday when asked about Kennedy’s comments. “I do know the total number that dropped off — 1.5 million — is far lower than the number that had been projected by others.”