Trump-Backed Julia Letlow Formally Launches Louisiana GOP Senate Primary Challenge to Sen. Bill Cassidy
Rep. Julia Letlow formally launched a U.S. Senate campaign in Louisiana, turning former President Trump’s public “Complete and Total Endorsement” — including a social‑media exhortation to “RUN, JULIA, RUN!!!” — into an official primary challenge to incumbent Sen. Bill Cassidy, with her announcement coming the day after Trump’s encouragement and delivered at a Greater Baton Rouge Business Report breakfast. Cassidy said Letlow called him and he intends to seek re‑election and win, while the contest has exposed GOP fractures — Senate leader John Thune backing Cassidy as the Senate Leadership Fund stays largely neutral — and outside players like MAHA PAC (with ties to RFK Jr.) have pledged $1 million to support Letlow.
📌 Key Facts
- Rep. Julia Letlow has formally launched a U.S. Senate campaign in Louisiana, turning President Trump's public encouragement into an official GOP primary challenge to incumbent Sen. Bill Cassidy.
- Trump publicly urged Letlow to run and posted a "Complete and Total Endorsement" on social media — including the lines "RUN, JULIA, RUN!!!" and calling her a "TOTAL WINNER!" and a "Great Star."
- Letlow announced her campaign at a Greater Baton Rouge Business Report breakfast the day after Trump's encouragement; she reportedly called Cassidy the morning of her announcement to tell him she respected him.
- Cassidy responded that he is "proudly running" for re‑election and is confident he will win, while many GOP colleagues appear "circumspect" about his prospects amid the primary challenge.
- The episode highlights a GOP leadership split: Senate GOP leader John Thune privately urged Trump to stick with Cassidy and was given a heads‑up call from Trump before the endorsement, but Thune has been unsuccessful in persuading Trump to back leadership's preferred incumbents.
- Practical campaign implications: the Thune‑aligned Senate Leadership Fund is expected to stay neutral in the Louisiana primary; the NRSC says it will back GOP incumbents but is not prioritizing Louisiana, making major committee or outside‑spending support for Cassidy unlikely.
- MAHA PAC, a group described as having ties to Robert F. Kennedy Jr., publicly pledged $1 million to support Letlow's expected primary challenge; MAHA PAC co‑founder Tony Lyons framed the move as supporting Trump's effort to "end the chronic disease epidemic" and praised Letlow as a "tireless champion for Louisiana families."
- Background context: Cassidy's relationship with RFK Jr. deteriorated after Cassidy, a pro‑vaccine physician, criticized Kennedy for cutting CDC advisory committee roles and imposing a new childhood vaccine schedule — actions that contradicted earlier assurances that influenced Cassidy's vote for Kennedy's nomination.
📰 Source Timeline (7)
Follow how coverage of this story developed over time
January 21, 2026
5:00 PM
Wednesday’s Campaign Round-Up, 1.21.26: Letlow to challenge Cassidy in Louisiana
New information:
- Confirms that Rep. Julia Letlow has formally launched a U.S. Senate campaign in Louisiana, turning Trump’s encouragement into an official primary challenge to Sen. Bill Cassidy.
- Reports that Cassidy has issued a public statement saying he intends to remain in the race and "win re-election."
- Notes that many of Cassidy’s GOP colleagues appear "circumspect" about his prospects, signaling growing intra-party doubt.
12:52 AM
Trump blows off Senate Republican leaders on critical endorsements
New information:
- Axios reports that despite Thune’s lobbying, Trump has refused to endorse incumbent Sens. John Cornyn and Susan Collins and has even publicly called for Collins’ ouster after her Venezuela war‑powers vote.
- The Thune‑aligned Senate Leadership Fund is expected to stay out of the Louisiana primary while its affiliates are channeling millions to defend Cornyn and has just committed $42 million to protect Collins in Maine.
- NRSC Chair Tim Scott has reiterated that the committee will back all GOP incumbents, but Louisiana is not among the eight battleground states the NRSC is currently prioritizing, meaning Cassidy is unlikely to get major committee or SLF outside‑spending help despite leadership’s personal support.
- Axios underscores that Thune is now "0 for 3" in late‑cycle efforts to get Trump on board with leadership’s preferred incumbents, underscoring a broader fracture in the GOP Senate campaign apparatus.
January 20, 2026
11:22 PM
Republican Sen. Bill Cassidy facing Trump-backed primary challenger
New information:
- CBS confirms the timing that Letlow’s announcement came the day after Trump publicly encouraged her to enter the race.
- The segment frames Cassidy as a 'frequent critic' of Trump, underscoring the ideological rift motivating the challenge.
- Adds expert reaction: CBS political strategists Laurie Watkins and Alex Conant analyze the primary’s implications for intra‑party dynamics, though without major new factual claims beyond the announcement itself.
3:50 PM
Rep. Julia Letlow jumps into Louisiana Senate race with Trump's backing
New information:
- Julia Letlow publicly announced she is running for the U.S. Senate at a Greater Baton Rouge Business Report breakfast, citing Trump’s endorsement and encouragement.
- Bill Cassidy said Letlow called him the morning of her announcement to tell him she is running and to say she respected him and believed he had done a good job.
- Cassidy responded that he will continue to do a good job 'when I win re-election,' framing himself as a conservative focused on improving life in Louisiana and the U.S.
- The article reiterates Trump’s Truth Social language calling Letlow a 'TOTAL WINNER!' and a 'Great Star' and promising his 'Complete and Total Endorsement' if she ran.
1:55 PM
Trump endorsement rocks Louisiana Senate race as Letlow poised to jump in
New information:
- Details that Trump publicly issued a 'Complete and Total Endorsement' of Rep. Julia Letlow on social media with the line 'RUN, JULIA, RUN!!!' if she enters the race.
- Report that Letlow is now likely to launch a Senate campaign as early as this week, after signaling she would not run without Trump’s backing.
- Confirmation that Senate Majority Leader John Thune personally continues to back Cassidy and that Trump called Thune the day before to give him a heads‑up on the endorsement.
- Disclosure that the Senate Leadership Fund, the main GOP Senate super PAC aligned with Thune, will stay neutral in the Louisiana primary despite earlier NRSC support for Cassidy.
- Cassidy’s public response post‑endorsement, saying he is 'proudly running' for reelection and is confident he will win even if Letlow runs.
January 19, 2026
4:42 PM
Cassidy was the key vote for RFK Jr. Now, a group with ties to Kennedy is backing the senator’s likely challenger.
New information:
- MAHA PAC, a group with close ties to HHS Secretary Robert F. Kennedy Jr., has publicly pledged $1 million to support Rep. Julia Letlow’s expected primary challenge to Sen. Bill Cassidy.
- MAHA PAC co‑founder Tony Lyons framed the move as backing Trump’s effort to 'end the chronic disease epidemic' and called Letlow a 'tireless champion for Louisiana families.'
- The article details the deterioration of the Cassidy–Kennedy relationship: Cassidy, a pro‑vaccine physician, has blasted RFK Jr. for cutting childhood vaccine recommendations, firing all 17 members of CDC’s independent vaccine advisory committee, and then bypassing that panel to impose a new European‑style childhood schedule.
- It confirms Cassidy’s earlier rationale for supporting Kennedy’s nomination — that Kennedy promised to maintain the CDC advisory panel’s recommendations — and notes those assurances were quickly broken.
- Senate GOP leader John Thune had urged Trump privately to stick with Cassidy, underscoring intra‑party divisions over the primary.
January 18, 2026