Balance of Power: 2026 Midterms

Resolution Criteria

This market will resolve according to the result of the 2026 United States midterm elections. A party will be considered to have 'control' of the House of Representatives, if they win a majority of voting seats. A party will be considered to have 'control' of the Senate if they have more than half of the voting Senate members, or half of the voting Senate members and the Vice President. A candidate's party is determined by their ballot-listed or otherwise identifiable affiliation with that party at the time the 2026 United States midterm elections are conclusively called by this market's resolution sources. A candidate without a ballot-listed affiliation to either the Democrat or Republican Parties will be considered a member of one of these parties based on the party that they most recently expressed their intent to caucus with at the time the 2026 United States midterm elections are conclusively called by this market's resolution sources. If control of the House is ambiguous given the above rules, this market will resolve according to the party affiliation of the first Speaker of the US House who is selected following the 2026 United States midterm elections. If control of the Senate is ambiguous given the above rules, this market will resolve according to the party affiliation of the first Majority Leader of the US Senate who is selected following the 2026 United States midterm elections. The resolution source for this market is the Associated Press, Fox News, and NBC. This market will resolve once all three sources have conclusively called winners of the House and Senate in the 2026 United States midterm elections. If all three sources do not achieve consensus in calling the relevant races for this market, it will resolve based on the official certification.

The 2026 United States midterm elections will determine which party controls the House of Representatives and the Senate, with four principal outcomes tracked in this market. Trading is heavily concentrated on two scenarios: a Democratic sweep and a split result in which Republicans hold the Senate while Democrats control the House. Resolution follows official calls by the Associated Press, Fox News, and NBC, with a deadline of 3 November 2026.

Market structure

Five outcomes are tracked: Democratic sweep, Republican sweep, Democratic Senate with Republican House, Republican Senate with Democratic House, and Other. Volume is heavily concentrated on two outcomes, with a Democratic sweep and a Republican Senate paired with a Democratic House together accounting for the overwhelming majority of activity. The remaining three outcomes attract notably smaller shares. Resolution requires consensus calls from the Associated Press, Fox News, and NBC, falling back to official certification if consensus is not reached.

Background

United States midterm elections are held in the middle of a presidential term and determine all 435 seats in the House of Representatives and roughly one third of the 100 Senate seats. Historically, the party holding the White House tends to lose ground in midterms, though the scale of any swing varies considerably. The 2026 cycle takes place against a backdrop of a Republican-controlled Congress and a Republican White House, with Democrats defending a map in the Senate that includes several competitive states. Control of either chamber shapes the legislative agenda, the budget process, and the executive branch's ability to advance its priorities for the remainder of the presidential term.

Key factors

Senate geography is a central structural variable: the seats contested in 2026 reflect the class elected in 2020, and the distribution of competitive races across red, blue, and purple states will determine whether either party can shift the chamber. In the House, single-seat plurality elections in individually drawn districts mean that national swing translates unevenly into seat changes; redistricting outcomes and incumbency advantages create friction between vote share and seat share. Presidential approval ratings at the time of the election historically correlate with midterm performance for the incumbent party. Candidate recruitment, fundraising, and late-breaking national events — economic data releases, legislative controversies, or judicial decisions — can shift competitive races in the final weeks. Turnout models, particularly in lower-salience midterm environments, introduce additional uncertainty in close districts and states.

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