There have been some interesting changes this week in the Kalshi probabilities for each state in the 2026 senate midterms. We currently predict that the Democrats will win 51 seats, and the Republicans 49, but 5 seats (Texas, Alaska, Ohio, Iowa, Nebraska) are tossups where the leading party only has a sight advantage. To see the change since our last article, toggle on "Change from May 27"
Overview:
Primaries have finished in many states, and the candidates for each party have grown more clear. The most recent primary was the Maine Senate primary, in which Graham Platner won the Democratic nomination and Susan Collins won the Republican nomination (uncontested). There's been a big shift in the Maine election due to controversy surrounding Graham Platner, which will be discussed in later sections. The Senate remains in extreme contention, with no party heavily favored to win.
Good news for Republicans:
It has been a good few weeks for Republicans, who have picked up gains in many key states. The most obvious one is Maine, which has shifted nearly 10 points to the right. Graham Platner has had recent allegations of sexual assault and other misconduct, which temporarily tanked his odds of winning the Senate election. In the span of a week, he went from an 80% chance of winning to almost a 50% chance of winning, which went up to 66% following a successful primary.
He will face Susan Collins in the general election, a relatively unpopular congresswoman who should be an easy candidate to beat. Platner's controversial past, especially in such a close state, might not bode well for Democrats. Although he remains ahead in polling for now, Platner's past could potentially ruin Democratic chances of winning the state.
Republican odds of winning Michigan have also improved slightly after Abdul El-Sayed became the clear frontrunner for the Democratic primary. El-Sayed is a progressive candidate, and in a state as close as Michigan he might scare off centrist voters who would have otherwise voted for a Democrat.
Good news for Democrats:
This week clearly favored Republicans, but there has also been an uptick in Democrat chances.
The most obvious one is in Louisiana, where odds have shifted 11 points to the left. We discussed this in detail in our article from May 27, but Lousiana remains heavily favored to go to the Republicans
Democrats also saw gains in Ohio, where former senator Sherrod Brown won the Democratic primary, facing off against Jon Husted. The election will be a special election to fill J.D. Vance's former seat. Brown has lead Husted by around 3% in many polls, and Democrat chances of winning Ohio are nearing 60%. Ohio is a key state that Democrats became favored to win just weeks ago,
Conclusion:
This week, and the previous month, has heavily favored Republicans in terms of electoral shifts. Democrats are now the slight underdogs to win the senate: