Bill Cassidy’s vaccine advocacy is putting his Senate future in peril as contends with MAHA

2026 ElectionBill Cassidy contends with MAHA in Washington and LouisianaThe Louisiana senator’s primary Saturday has been defined by conflict with Trump, including disagreements over the new health-focused members of his coalition.Listen to this article with a free account00:0000:00Sen. Bill Cassidy, R-La., speaks with reporters at the U.S. Capitol in September.Kent Nishimura / Getty ImagesShareAdd NBC News to GoogleMay 14, 2026, 5:00 AM EDTBy Brennan Leach and Melanie ZanonaSen. Bill Cassidy’s advocacy for vaccines and his résumé as a doctor have defined his political career.Subscribe to read this story ad-free Get unlimited access to ad-free articles and exclusive content.Now, those credentials are putting his Senate future in peril as Cassidy, R-La., prepares for the most difficult primary of his life Saturday.Members of the “Make America Healthy Again” movement — a separate but overlapping wing of the MAGA movement that fully fused with President Donald Trump’s coalition in 2024 — have been working hard to take Cassidy down and install Trump-backed Rep. Julia Letlow as the Republican nominee for the Senate in deep-red Louisiana. Cassidy was the key vote to confirm Robert F. Kennedy Jr., a longtime anti-vaccine activist, as health and human services secretary. But since then, Cassidy, a physician who is pro-vaccine, has found himself in conflict with Kennedy and his allies, including months of clashes with Kennedy over his vaccine skepticism and his actions at the Department of Health and Human Services.And while Cassidy’s vote to convict Trump on Jan. 6-related impeachment charges in 2021 also made him a target of the right, it’s the tense relationship between Cassidy and Kennedy’s MAHA movement that has really boiled over ahead of the primary. Early this month, Trump blamed Cassidy — who chairs the Health, Education, Labor and Pensions Committee — for standing in the way of Dr. Casey Means’ nomination to be surgeon general, forcing Trump to replace her with a n...