Kennedy allies target Senator Bill Cassidy in Louisiana primary fight

Robert F. Kennedy Jr.’s allies are using Louisiana’s Republican Senate primary to settle a score with Bill Cassidy, turning a state race into a test of loyalty inside the GOP coalition. A Kennedy-aligned MAHA PAC spent $116,878.20 from May 2 through May 5 on digital ads, mailers and text messages aimed at Cassidy and boosting Rep. Julia Letlow.

The pressure campaign comes as Cassidy, a physician and chairman of the Senate Health, Education, Labor and Pensions Committee, faces a primary on May 16, 2026, against Letlow and former Rep. John Fleming. Louisiana’s election rules could force a runoff if no candidate tops 50 percent, raising the stakes for a campaign that now carries the imprint of Washington’s bitter health-policy wars.

The target is no accident. Cassidy played a pivotal role in Kennedy’s confirmation as health secretary after extracting commitments from Kennedy that he would not undermine public confidence in vaccines. Since then, Cassidy has clashed publicly with Kennedy over vaccine policy and other health issues, and Democrats have accused Kennedy of misleading Cassidy about those promises. What is unfolding now is less a routine intraparty feud than an enforcement mechanism: a sitting senator who helped clear a Cabinet nomination is being punished for drawing a line on vaccines.

The confrontation escalated further after President Donald Trump withdrew Casey Means as his surgeon general nominee on April 30 and blamed Cassidy for blocking the nomination, calling him “very disloyal.” That intervention sharpened the sense that Cassidy is no longer dealing only with a rival primary but with a broader effort from the Trump-Kennedy orbit to define who counts as faithful inside the party.

The money trail shows how serious that effort has become. The MAHA PAC’s total spending in the Louisiana race has now exceeded $391,000 since mid-March, and Tony Lyons, the group’s president, has pledged $1 million to help defeat Cassidy. An Emerson College poll released last week showed Fleming at 28 percent, Letlow at 27 percent and Cassidy at 21 percent, a split field that leaves the incumbent vulnerable if anti-Cassidy forces coalesce.

For Kennedy and his allies, the Louisiana contest is about more than one Senate seat. It is a warning that vaccine policy, personal allegiance and movement discipline now carry electoral consequences, and that the terms of the Republican coalition are increasingly being set by a health secretary willing to use his power against a senator who crossed him.