What is midterms
Executive summary
Midterm elections are the general federal elections that occur roughly halfway through a U.S. president’s four‑year term and put control of Congress — all 435 House seats and about one‑third of Senate seats — on the ballot [1] [2]. They are widely treated as a referendum on the president’s party because midterms often change the balance of power in Congress and therefore shape what legislation can pass or be blocked for the remainder of a presidency [3] [4].
1. What midterms are, in plain terms
A “midterm” is the even‑year general election that falls two years after a presidential election and two years before the next one; it is when voters elect all members of the House of Representatives (two‑year terms) and roughly one‑third of U.S. senators (six‑year terms), plus many governors and state and local officials in dozens of states [1] [2] [3].
2. Why midterms matter for power in Washington
Because Congress writes laws, confirms many presidential appointments and controls oversight, which party holds the House and Senate determines whether the president can advance key priorities or face gridlock; historically the president’s party usually loses seats in midterms, altering the legislative agenda and oversight dynamics [3] [5] [4].
3. The mechanics: what’s on the ballot and when
Midterms take place on Election Day — the Tuesday after the first Monday in November — and can include all 435 House seats, about 33–35 Senate seats depending on the cycle, roughly three dozen gubernatorial contests in most cycles, and a host of state and local races and ballot measures that vary by state [1] [6] [2].
4. Patterns, exceptions and the “referendum” effect
Political scientists and historical records show a strong pattern: the president’s party tends to lose House seats (averages cited range from mid‑20s to near 28 seats across different studies) and some Senate seats in midterms; commentators therefore describe midterms as a referendum on the president’s job performance, though factors like approval ratings, the number of vulnerable seats, redistricting and local conditions also shape outcomes [1] [5] [7].
5. Turnout and who shows up to decide them
Midterm turnout is consistently lower than presidential years: over recent decades presidential elections draw about 50–60% of eligible voters while midterms commonly see about 40% turnout, with exceptions such as 2018 which saw unusually high participation [1] [5]. Lower turnout amplifies the influence of motivated constituencies, interest groups and get‑out‑the‑vote operations [8].
6. Strategic and institutional levers that shape midterms
Beyond voters’ moods, structural factors — staggered Senate terms, state redistricting maps, retirements, legal challenges to districting and changes in voting rules — can tilt the playing field; reporting in 2026 underscored how redistricting and court decisions (including potential Voting Rights Act changes) and mid‑decade map redraws could materially affect which party benefits [9] [10].
7. Competing narratives and agendas to watch
Advocates and parties frame midterms either as corrective checks on presidential power or as obstacles to governance; think tanks and media highlight predictable midterm losses for the president’s party as structural, while campaign operatives emphasize turnout, messaging and local races. Some reporting and analysis — including Brookings and Institut Montaigne — urge reading midterms as both structural and contingent, influenced by approval ratings, district maps and mobilization [7] [4].
8. What reporting does not settle here
Sources consistently describe the mechanics, historical patterns and stakes of midterms (p1_s1–[11]4), but they do not resolve every causal question — for example, how much any single factor (economy, president’s approval, redistricting, turnout operations) will determine a specific midterm outcome in a given year — and those uncertainties require cycle‑specific analysis beyond these general sources [7].