- Will Republican Senate incumbents not win in exactly two nominating elections in the 2026 cycle?37¢
- Will Republican Senate incumbents win all their nominating elections in the 2026 cycle?<1¢
- Will Republican Senate incumbents not win in exactly one nominating election in the 2026 cycle?<1¢
- Will Republican Senate incumbents not win in exactly three nominating elections in the 2026 cycle?55¢
- Will Republican Senate incumbents not win in exactly four nominating elections in the 2026 cycle?<1¢
- Will Republican Senate incumbents not win in more than four nominating elections in the 2026 cycle?<1¢
The 2026 midterm elections are scheduled to be held on November 3, 2026, with congressional primaries running from March through September. This market will resolve according to the number of Republican Senate incumbents who do not win their nominating election to move on to the general election as a result of the 2026 midterm primary elections. An incumbent will be considered not to have won their election if they are not declared the winner of the election they sought, including if they withdraw, suspend, or otherwise leave the race at any point after officially registering as a candidate, regardless of the reason. Incumbents who do not officially register as candidates for reelection will not be considered. This market will resolve based on the results of all Senate nominating elections, including party primaries, top-two or jungle primaries, and primaries for special elections, that are scheduled to occur between March 1 and September 30, 2026. If a required runoff for any such election or a subsequent qualifying round in a non-partisan primary system could change the market’s outcome, the market will remain open until that contest is conclusively called by this market’s resolution sources. A candidate's party will be determined by their ballot-listed or otherwise identifiable affiliation with that party at the time of their nominating election. A candidate without a ballot-listed affiliation to either the Democratic or Republican parties will be considered a member of one of these parties based on the party with which they most recently expressed their intent to caucus prior to the conclusion of the relevant nominating election. The resolution source for this market will be the Associated Press, Fox News, and NBC. This market will resolve once all three sources have conclusively called all relevant nominating elections. If all three sources do not achieve consensus in calling the relevant races for this market, it will resolve based on official state certification of the nominating election results.
Two confirmed primary defeats—Bill Cassidy in Louisiana and John Cornyn in Texas—have established a floor of two Republican Senate incumbent losses, with trader consensus now favoring three at 55% amid remaining contests. These outcomes stemmed from strong challenges by Trump-aligned candidates capitalizing on intra-party tensions and base dissatisfaction with establishment records. Most other GOP incumbents, including Roger Marshall in Kansas and Dan Sullivan in Alaska, have advanced or face limited opposition in August and September primaries, consistent with historical patterns of low Senate primary turnover. Upcoming vote counts in contested states could determine whether a third upset materializes before all nominating contests conclude.