Who is Sen. Bill Cassidy, MD? A pivotal RFK Jr. vote

Senator Bill Cassidy, MD (R-Louisiana)

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Sen. Bill Cassidy, MD (R-Louisiana), a practicing physician-turned-legislator, is at the center of a contentious confirmation process for Robert F. Kennedy Jr., President Donald Trump’s nominee for Secretary of the U.S. Department of Health and Human Services (HHS). As Chairman of the Senate Health, Education, Labor and Pensions (HELP) Committee, and a member of the Senate Finance Committee, Cassidy has had his chance to question Kennedy on key public health issues, particularly regarding vaccine safety, chronic disease prevention and health care affordability.

Cassidy, a Republican, has made it clear that he is still undecided on his vote at the conclusion of Kennedy’s second hearing.

Challenging Kennedy

During the HELP Committee hearing, Cassidy acknowledged areas of agreement with Kennedy, including the need to address ultra-processed foods and obesity rates. However, he expressed his concern over Kennedy’s past skepticism of vaccines.

“It’s no secret I have some reservations about your past positions on vaccines,” Cassidy said in his opening statement.

He would later press Kennedy to unequivocally affirm that the measles and hepatitis B vaccines do not cause autism. Although Kennedy eventually conceded that, if presented with what he considered to be definitive data, he would support such claims—and even go so far as to “apologize for any statements that misled people otherwise”—Cassidy remained skeptical of his commitment to safe public health messaging.

Cassidy also questioned Kennedy about whether he would ensure that U.S. Centers for Disease Control (CDC) recommendations are solely based on peer-reviewed, widely accepted science rather than personal beliefs. Kennedy assured the committee that he would uphold evidence-based standards but again faced pushback over past statements that cast doubt on vaccine safety.

From physician to politician

Cassidy, born in 1957, in Highland Park, Illinois, was raised in Baton Rouge, Louisiana. He would go on to receive a bachelor’s degree in biochemistry, as well as a medical degree, from Louisiana State University (LSU). While at LSU, Cassidy met his wife, Laura Cassidy, MD, a retired general surgeon specializing in breast cancer.

Cassidy himself worked as a gastroenterologist, specializing in liver disease, for more than three decades prior to entering politics.

Cassidy would later return to the LSU Medical School, where he taught medical students and residents at Earl K. Long Hospital, a hospital for the uninsured. He is the co-founder of the Greater Baton Rouge Community Clinic, which provides free dental and health care to the working uninsured, and he’s the creator of a private-public partnership to vaccinate 36,000 greater Baton Rouge area children against hepatitis B, at no cost to schools or parents.

In the aftermath of Hurricane Katrina in Louisiana, Cassidy helped convert an abandoned department store into an emergency health care facility for those impacted by the hurricane.

Cassidy’s political career began in 2006, when he was elected to the Louisiana State Senate. He later won a seat in the U.S. House of Representatives in 2008, before securing his current Senate position in 2014. Since then, he has served on the Finance Committee, the Energy and Natural Resources Committee and the Veteran Affairs Committee, in addition to the HELP Committee, of which he has been Ranking Member/Chairman since 2023.

A physician’s perspective

Cassidy’s tenure as a physician profoundly shaped his approach to health policy, particularly regarding immunization programs and public health infrastructure. During Thursday’s HELP Committee hearing, Cassidy shared a defining moment from his medical career—watching an 18-year-old patient suffer acute liver failure due to hepatitis B, a disease preventable by vaccination.

The experience reinforced Cassidy’s stance on vaccines, which he pressed Kennedy to clarify during the hearings.

Cassidy’s decision

Despite positioning himself as a health care pragmatist, Cassidy’s role as a Republican senator and his relationship with the Trump administration will play a significant role in his decision-making process.

During the hearing, Cassidy underscored the importance of Kennedy’s role in shaping President Trump’s health care legacy. “Any action you take as HHS Secretary will shape [President Trump’s] legacy, and we both want that legacy to be positive,” Cassidy said.

With Kennedy’s nomination deeply polarizing and politicized, Cassidy’s vote is one to watch closely. As HELP Committee Chairman, his support has the potential to influence other senators who remain undecided on Kennedy’s confirmation.

Although he has not publicly committed to a final decision, Cassidy’s line of questioning and emphasis on vaccine policy indicate that he has his doubts, remaining a crucial figure in determining whether Kennedy will lead the nation’s top health agency, and become the nation’s top public health official.

As Thursday’s hearing wrapped up, Cassidy told Kennedy that the two would likely talk further over the weekend, before a final decision is expected next week.