Cassidy's Polling Day Peril in Louisiana

Voters in Louisiana are heading to the polls on Saturday for a Republican Senate primary that has become a pivotal moment in Bill Cassidy’s political career. The race has intensified due to the ongoing impact of Cassidy’s 2021 vote to convict former President Donald Trump during his impeachment trial. This decision continues to resonate within Louisiana's Republican electorate, making the path to re-election increasingly difficult for Cassidy.

The primary is being viewed as a significant test of loyalty to Trump within the party. Cassidy faces strong competition from Julia Letlow and John Fleming, with the contest shaped by Trump’s efforts to remove the incumbent. Recent polling and prediction markets suggest that the race is highly uncertain, with no candidate consistently exceeding 50% support. However, Letlow appears to be leading in prediction markets, even though public polls show a more fragmented landscape.

Louisiana Republicans are voting today in what is considered a “semi-closed” party primary for the U.S. Senate. This system allows eligible voters to choose a party ballot at the polls but locks them into that choice for any subsequent runoffs. This setup can amplify the influence of base-driven outcomes in low-turnout contests, which is particularly relevant in this race.

Key Points To Know:

• Louisiana Republicans are voting today, May 16, in a semi-closed primary for the U.S. Senate.
• The race features Cassidy, Julia Letlow, and John Fleming.
• Public polling shows a lack of clear frontrunner, with Cassidy trailing both Letlow and Fleming.
• Prediction markets indicate Letlow is leading, despite polling suggesting a more fragmented race.
• A sitting senator is at risk of being eliminated before November, testing whether Trump-loyalty politics can unseat an incumbent who broke with the president.
• The winner of the GOP nomination is heavily favored in the general election in deep-red Louisiana, making today’s contest crucial.

A Primary Shaped By Trump And A New Election System

Louisiana is holding party primaries for the U.S. Senate today, with any necessary runoff scheduled for June 27. Unlike the previous "jungle primary" system, eligible voters are now funneled into party-specific ballots for certain offices, including the U.S. Senate. No-party voters can choose a party ballot at the polls but are then locked into that choice through a runoff, which can affect coalition dynamics in a two-step contest.

This shift in rules comes amid a Republican civil war centered around loyalty to Trump. Letlow entered the race with Trump’s backing and positioned herself as the candidate most aligned with his agenda, while Fleming presented himself as a more reliably conservative option. Cassidy, on the other hand, argued he could work with Trump’s administration while defending his impeachment vote as a matter of principle—an argument that may not resonate with a primary electorate where Trump remains popular.

The Central Vulnerability: The Impeachment Conviction Vote

The core issue affecting the race is Cassidy’s vote to convict Trump after the January 6 Capitol Hill riots. Trump has not forgotten this decision and has publicly urged Louisiana Republicans to vote against Cassidy, effectively nationalizing what would otherwise be a local contest.

In a normal cycle, incumbency, donor networks, and name recognition create a high floor. Closed primaries can lower that floor by narrowing the electorate to the most habitual and partisan voters—exactly the group most responsive to elite cues like endorsements and grievance politics. Analysts are watching whether Cassidy can make the runoff, not just whether he can win it.

What The Polling Shows

Public polling has been inconsistent, with different firms presenting varying stories. However, recent surveys share a common theme: no one is consistently above 50%, and Cassidy is frequently behind.

A Quantus Insights survey of 1,015 likely voters conducted between May 6 and 7, 2026, showed Letlow leading with 42%, followed by Fleming at 30%, and Cassidy at 20%. In a hypothetical runoff between Cassidy and Letlow, Letlow led 63% to 23.4%. In a Cassidy–Fleming runoff, Fleming led 55.1% to 24.6%.

A Republican-sponsored Fabrizio, Lee & Associates survey for the Accountability Project of 600 likely Republican primary voters showed Letlow at 32%, Cassidy at 26%, and Fleming at 21%. An Emerson College poll found Fleming leading narrowly at 28%, Letlow at 27%, and Cassidy trailing at 21%.

What The Markets Are Pricing In

Prediction markets suggest Letlow is the favorite, with Polymarket pricing her at around 76% and Kalshi listing her at about 94%. These markets aggregate trader beliefs but should be treated as one indicator among many, not a substitute for actual votes.

What Happens Next

Polls are set to close across Louisiana at 8 p.m. local time (9 p.m. ET) on Saturday, with initial results expected shortly after. Full returns will come into focus over the following hours.