- The betting markets treat Saturday’s Louisiana Republican Senate runoff as close to settled. Polymarket prices Rep. Julia Letlow at 87% to win the nomination and state Treasurer John Fleming at 13%, on more than $456,000 of volume.
- In plain stakes, a bet on Letlow risks about 87 cents to win 13, while a bet on Fleming risks 13 to win about 87, the classic shape of a heavy favorite against a long shot.
- The line has only hardened. Letlow opened near 66% when she entered in January and has climbed to 87% after winning the May 16 primary with President Trump’s endorsement.
- November is already priced in. The market gives the Republican nominee about 92% to win the seat, in a state that has not sent a Democrat to the Senate since 2008.
- The runoff exists because incumbent Bill Cassidy collapsed. He finished third in his own primary, a historic fall for a sitting senator, five years after his vote to convict Trump.
BATON ROUGE – If you are looking for a coin flip, look somewhere other than Louisiana. Heading into Saturday’s Republican Senate runoff, the betting markets have all but handed the nomination to Rep. Julia Letlow. Polymarket prices her at 87% to beat state Treasurer John Fleming, who sits at 13%, on a market that has churned more than $456,000. And because no Democrat has won a Louisiana Senate seat since 2008, the winner Saturday is, in the market’s eyes, the next senator. The runoff, not November, is the whole ballgame, and even the runoff looks close to over.
The Runoff Line: Letlow 87, Fleming 13
Start with the number that matters. Letlow’s 87% on Polymarket is the price of a near-lock. In betting terms, a Yes share on her costs about 87 cents and pays a dollar if she wins, so backing the favorite means risking roughly $87 to make $13. Fleming’s side is the mirror image: about 13 cents to win a dollar, or $13 to make $87. That is the math of a long shot, and the $456,000 in volume says traders are comfortable with it.
Kalshi tells the same story. Its Louisiana Republican nominee market likewise makes Letlow the favorite, and its contract on the seat itself prices the Republican above 90% for November. Two different books, one conclusion: Letlow is the pick, and it is not close.
How the Price Got Here
Letlow has been the market favorite almost from the day she got in. She opened near 66% when she entered in January, drifted into the low 70s by the May 16 primary, and pushed to 87% for the runoff. Each step tracked a real event: Trump’s endorsement in January, then a first-place primary finish of about 45% that left Fleming a distant second.
That steady climb matters for bettors because it shows no late wobble. There has been no Fleming surge, no scandal, no polling shock to move the line back toward a toss-up. Runoff polling has Letlow ahead by double digits, and the market has simply priced that lead in.
November Is Already on the Board
The reason the runoff carries so much weight is the general election behind it. On the wider board of 2026 Senate odds, Louisiana barely registers as a contest: Polymarket gives the Republican nominee about 92% to hold the seat, with the Democrat near 8% on thin volume. Every major rating calls it safe Republican. Win Saturday’s runoff, and the seat is essentially won, which is why the smart money is focused on the party contest rather than the fall.
Where the Only Value Sits
For anyone hunting an underdog, Fleming at 13% is the lone live ticket. The state treasurer and former congressman, who served in Trump’s first administration, has self-funded a hard-right campaign built on his MAGA record and his opposition to carbon capture, a real fault line in Louisiana. To cash, he would need a low-turnout runoff and near-total consolidation of the anti-Letlow vote. The market gives that about a one-in-eight chance, which is exactly why the payout is large.
The Democratic runoff is its own long shot. Across the broader Louisiana race odds, Jamie Davis, the party-endorsed candidate who led the Democratic primary, faces consultant Gary Crockett, who slipped into second by fewer than 300 votes. Whoever wins lands on the roughly 8% side of the November market, and neither Democrat changes the math.
How Cassidy Handed Over the Seat
None of this would be happening if the incumbent had held serve. Bill Cassidy finished third in the May 16 primary with about 25%, behind both challengers, and became the first sitting senator to lose renomination since 2012. His 2021 vote to convict Trump after the Capitol riot dogged him for years, and once Trump endorsed Letlow in January, the markets put Cassidy in the single digits and never looked back. He is now a cautionary tale priced into every line on this race.
The Bet Board
Add it up and Louisiana is one of the most lopsided cards on the calendar. Letlow sits at 87% for the nomination, Fleming at 13%, and the Republican side is near 92% to keep the seat in the fall. The Democratic nominee, still to be decided, is the 8% leftover. The only question Saturday is whether a sleepy June turnout lets Fleming sneak through, and at 87-13 the market is betting it will not. One reminder for readers: those figures are win probabilities the books are pricing, not projected vote shares.
What to Watch Saturday
Polls close Saturday evening. Because Letlow led the primary by about 17 points, an early Fleming lead would be the first real crack in the 87% line; anything short of that, and the Trump-backed congresswoman becomes the November favorite on the spot. For the latest election odds, Louisiana is the rare race where the market expects the result before a single runoff vote is counted, with the general election a formality in a state this red.
