5.9 - Congressional Elections
Structure of Congressional Elections
Senators serve 6-year terms, representatives serve 2-year terms. Every even-numbered year, the whole House and a third of the Senate face reelection.
- Presidential election years: turnout is much higher, and results can be swayed by how people feel about the presidential candidates.
- Midterm elections: lower turnout, more partisan and ideological voters. The president's party almost always loses seats, likely because opponents of the president are more motivated to show up and check his power. This pattern held under Biden, Trump, and Obama.
- Examples: Republicans gained 63 House seats in 2010 (under Obama), Democrats gained about 40 in 2018 (under Trump), and Republicans gained 9 in 2022 (under Biden). The rare exceptions in the past century were 1934, 1998, and 2002, when the president's party gained House seats.
- Coattail effect: a popular presidential candidate can help their party's candidates for Congress win in the same election.
Primaries and Caucuses in Congressional Races
House and Senate nominees are chosen in state-run primaries, open or closed depending on the state (see 5.8). A few states also use party caucuses or conventions; in Utah, for example, candidates can earn a spot on the primary ballot at a party convention.
- Primaries in safe seats: where one party always wins, the primary is the real contest. Primary voters tend to be more partisan, so candidates often move toward their party's base, and many incumbents fear a primary challenge more than the general election.
The Incumbency Advantage
Incumbency is the single best predictor of who wins a congressional race, with incumbents historically winning 90 to 98 percent of the time, even in a bad year, they still win around 85 percent.
Senate incumbents are a bit less safe than House incumbents. Senators represent whole states, which can't be gerrymandered, and they often face well-known, well-funded challengers.
Why incumbents win so often:
- Casework: helping constituents navigate bureaucracy or access benefits builds goodwill.
- Name Recognition: better known, more media access.
- Franking Privilege: free mail to remind constituents of accomplishments, without dipping into campaign funds.
- Staff and Experience: bigger teams, more campaign know-how.
- PAC Contributions: most PAC money goes to incumbents.
- Gerrymandered Districts: many incumbents sit in safe seats drawn specifically to be uncompetitive.
- The required cases limit how lines can be drawn: Baker v. Carr (1962) led to the rule that districts must have roughly equal populations, and Shaw v. Reno (1993) ruled that race can't be the only factor in drawing a district. Drawing lines to help a party (partisan gerrymandering) is still allowed under federal law, since the Court ruled in Rucho v. Common Cause (2019, not a required case) that federal courts can't hear those cases.
Big picture
Congressional elections follow the rhythm of the presidential cycle, high turnout in presidential years, lower and more partisan turnout in midterms, where the president's party usually loses ground. But the biggest factor by far is incumbency, powered by casework, name recognition, franking privileges, and safe, gerrymandered districts.