Kalshi and Polymarket anticipate that the Democratic Party will sweep both the House and the Senate in the midterm elections slated for November. There is a close to 50% chance of this outcome, while the second option, where Democrats win the House but lose the Senate, reaches 37%.
Prediction markets, including Polymarket and Kalshi, rose to notoriety after forecasting Donald Trump’s victory, while traditional polls envisioned Kamala Harris would win the 2024 U.S. presidential election.
Now, these same platforms are predicting that Democrats will get control of both the House and the Senate in the upcoming November midterms.
Prediction market contracts available, which measure the odds of each party winning control of one of two houses, or sweeping both, estimate that Democrats have a nearly 50% chance of retaking control of the U.S. Congress.

In opposition, participants measure the odds of a split result, with Democrats retaking control of the House and Republicans maintaining control of the Senate at over 35%.
The markets have evolved to this state just recently. In January, the leading prediction choice indicated a Democratic House and a Republican Senate as the most likely outcome of this event.
Most analysts believe that the U.S. participation in the conflict against Iran, as well as its consequences on gas and oil prices, have contributed to this shift. Even some Republican senators have openly referred to this subject.
At a recent interview on Fox, Senator Rand Paul commented on the effect of the Iran incursion on the results of the elections. He stated:
“I think high oil prices will be the problem. I think if you add in high gas prices, high oil prices, and if we are still bombing Iran, with kinetic action; people don’t want to call it war, but if there is still kinetic action that causes oil to be over a hundred dollars, I think you are going to see a disastrous election.”
Nonetheless, Trump himself has dismissed worries about the Iran conflict having a negative influence on the midterm elections. “People are loving what’s happening. We’re taking out a threat to the United States of America, a major threat, … and doing it like nobody’s ever seen before,” he told Politico on March 5.
Prediction markets like Polymarket and Kalshi gained attention by forecasting Trump’s victory and are now predicting Democratic control of Congress.
The markets estimate nearly a 50% chance for Democrats to retake control of both the House and the Senate.
There’s over a 35% chance that Democrats will control the House while Republicans maintain the Senate.
Analysts suspect that U.S. involvement in the Iran conflict and rising gas prices are contributing to shifts in voter sentiment.