The Senate voted 49-50 on Thursday against a resolution calling for an end to U.S. military action in Iran. The result is largely symbolic, but it lands less than six weeks before Election Day, right as the fight for Senate control heats up. The Senate contract on Kalshi has seen more than $36 million in trading volume, and our Kalshi review explains how the platform works. You can also download the Action Network app for more picks and analysis.
Senate Race on Kalshi
Prediction markets let traders buy and sell contracts tied to real-world events. On Kalshi's "Which party will win the Senate?" prediction market, each party has its own contract priced between 1¢ and 99¢, and that price reflects how likely the market thinks the outcome is. A contract settles at $1 if its outcome happens and $0 if it does not.
Prices shift as news comes in, so traders can also enter or exit well before Nov. 3. Republicans currently hold a 53-47 majority, so Democrats need a net gain of four seats to take control.
What Happened in the Senate on Thursday
Four Republicans, Susan Collins, Lisa Murkowski, Rand Paul and Thom Tillis, joined Democrats in voting "yes", while DemocratJohn Fetterman voted "no". Angela Alsobrooks did not vote because of a family matter, and her presence would not have changed the result. The measure was a concurrent resolution, so it would not have gone to the president's desk. It passed the House in July, and AP reported this was likely the last chance for senators to record a position on the war before November.
Each side framed it differently.
Sen. Tim Kaine, who has led the effort, called it "more than a message" and said Congress holds the power to declare war. Majority Leader John Thune called the vote "political." Alaska Republican Dan Sullivan argued the U.S. needs to restore deterrence against Iran.
Prices at home are part of the backdrop. Gas averages $4.48 a gallon, according to AAA, and Republican candidates in tight races, including Michigan's Mike Rogers and Iowa's Ashley Hinson, have said the war should end soon. Most GOP senators, including Ohio's Jon Husted and Sullivan, still voted "no".
Why the Senate Market Is Worth Watching This Week
The contract's chart tells the story. Republicans were strong favorites a year ago, the two sides ran close to even for much of the spring and summer, and Democrats have pulled clearly ahead over the past couple of weeks. They now lead, but not by enough to call it settled, and Republicans still hold a sizable share of the market.
Cook Political Report listed seven Senate toss-ups in mid-September: Alaska, Iowa, Maine, Ohio and Texas, all held by Republicans, plus Michigan and New Hampshire, held by Democrats. Thursday's vote touched several of them: Collins (Maine) voted "yes", while Sullivan (Alaska) and Husted (Ohio) voted "no".
Maine has its own market, but the chamber-wide contract folds every one of these races into one price. Early voting has already opened in some states, and lawmakers will spend nearly all of October campaigning, so new information will keep coming.
What could move the price next:
- Fresh polls in the toss-up states.
- Early voting turnout as more states open.
- Fuel prices and Iran headlines.
- Campaign ad spending and October debates.
That mix of a clear leader and real uncertainty makes the market interesting right now. Traders who think the recent move went too far, or not far enough, have less than six weeks to act on that view before the contract settles. Prices reflect what traders expect, not a guarantee.
