The Bill Cassidy Senate primary has become one of the most closely watched intraparty battles of the year, and not for reasons the two-term Louisiana Republican would have chosen. Once a comfortable incumbent, Cassidy now finds himself scrambling to survive a contest that could end his time in Washington.

A Sitting Senator Backed Into a Corner

Cassidy is no longer running as the favorite. He is running as the underdog, and possibly the loser. Conversations with roughly a dozen Republican officials, lawmakers, and strategists across Louisiana point to a shared expectation: the senator may not even secure a spot in a run-off when voters head to the polls on Saturday.

That outcome would be remarkable. A third-place finish, with no path forward, would not just end Cassidy’s career in the Senate. It would also hand President Donald Trump another trophy in his ongoing effort to punish Republicans who have defied him.

The root of Cassidy’s trouble traces back to a single decision. In 2021, he voted to convict Trump during the former president’s second impeachment trial. Five years later, that vote still defines how many Louisiana Republicans view him.

“When it comes to stabbing Trump in the back with that vote to impeach, the memories are very long,” said Kevin Berken, the Jefferson Davis Parish GOP chair, who is leaning toward backing one of Cassidy’s rivals.

Two Challengers, One Shared Target

Cassidy is squeezed between two opponents who have built their campaigns around MAGA energy.

The first is Rep. Julia Letlow, who carries Trump’s endorsement. The second is State Treasurer John Fleming, a former House Freedom Caucus member and a deputy chief of staff during Trump’s first term. Both have positioned themselves as the authentic conservative in the race, and both have benefited from lingering anger over Cassidy’s impeachment vote.

Polling reflects the senator’s weak standing. A late-April survey from Emerson College placed Cassidy at 21 percent, trailing Fleming at 28 percent and Letlow at 27 percent. The state Republican Party formally distanced itself from Cassidy after his impeachment vote, and Trump has publicly branded him disloyal while urging Louisiana voters to reject him.

A Revenge Tour With Light Footprints

Louisiana is only one stop in what has become a season of political retribution for Trump. Earlier in the month, he and his allies helped unseat five Indiana state lawmakers who resisted redrawing congressional maps to favor Republicans. After Saturday’s vote in Louisiana, attention shifts to Kentucky, where Rep. Thomas Massie faces his own primary on May 19.

Yet Trump’s involvement in Louisiana has been surprisingly restrained. He reaffirmed his support for Letlow in a Truth Social post, calling her dependable, and he took another jab at Cassidy over the impeachment vote. Beyond a handful of online messages, though, the president has stayed mostly on the sidelines. He has not campaigned in person for Letlow, and his enormous MAGA Inc. fundraising reserve, reported to exceed 300 million dollars, has not been deployed on her behalf.

Cassidy, for his part, says he is focused elsewhere. He told POLITICO that the impeachment vote belongs to the past and that his attention is on Louisiana’s future rather than a decision made five years ago.

The Health Policy Fights That Deepened the Divide

Cassidy’s friction with the MAGA base extends well beyond impeachment. As a physician serving in the Senate, he sharply questioned Robert F. Kennedy Jr. on vaccines during Kennedy’s confirmation hearing for Health and Human Services Secretary. He also helped block the nomination of health influencer Casey Means for Surgeon General.

Those moves angered the growing Make America Healthy Again movement. The Kennedy-aligned MAHA PAC has pledged to spend roughly 1 million dollars supporting Letlow in an effort to remove Cassidy from office, though whether that money shifts the result remains uncertain.

MAHA PAC leader Tony Lyons has argued that health policy now resonates strongly with voters, particularly undecided ones, and predicted that Letlow would prevail.

Cassidy’s Narrow Window of Hope

Despite the gloomy forecasts, Cassidy’s path is not entirely sealed. His best asset may be the division among his opponents.

With Letlow and Fleming both chasing the anti-Cassidy vote, that bloc is being split in two. The senator’s campaign believes this fracture, combined with the unusually high turnout of non-party voters in Louisiana’s closed primary, could push him into a run-off.

Campaign adviser Mark Harris acknowledged that Cassidy is unlikely to finish first, but argued the senator is well positioned to qualify for a second round and assemble a winning coalition from there.

Fleming, meanwhile, insists his consistency is what sets him apart. He has branded himself the most conservative option, pointing to his Freedom Caucus record. Some local officials agree. Berken said he trusts Fleming’s record and suspects Trump endorsed Letlow largely at the urging of Republican Gov. Jeff Landry.

A Race That May Come Down to the Booth

The closing days of the campaign have turned combative. Letlow and Fleming have increasingly attacked each other, a sign each expects the other in a run-off, or fears that a continued split could let Cassidy slip through.

Cassidy has aimed his energy almost entirely at Letlow, branding her “Liberal Letlow” and criticizing her past support for diversity initiatives in higher education, programs she has since disavowed. One unaffiliated Louisiana strategist described that strategy as self-destructive and predicted Fleming would finish on top.

Letlow has answered the incoming fire by leaning hard on Trump’s endorsement, treating it as proof of her MAGA credentials.

How voters respond may not be clear until the final moment. Jamey Sandefur, chair of the Livingston Parish GOP, said the race feels tight, with many undecided voters making up their minds only once inside the booth. He added that, while he has long doubted the power of endorsements, an unusual number of voters have told him Trump’s backing of Letlow could be the deciding factor.

For Cassidy, that is precisely the problem. The Bill Cassidy Senate primary has become a referendum on loyalty to Trump, and in Louisiana, that is a difficult test for any Republican who once voted to convict him.