AP Syllabus focus:
‘General elections for Congress include both presidential-year and midterm elections, shaping turnout and outcomes.’
Congressional general elections occur every two years, but the political environment differs sharply depending on whether they coincide with a presidential race. These differences shape who turns out, what issues dominate, and which party gains seats.
What “general elections” mean for Congress
General elections decide who will serve in the U.S. House of Representatives (all seats) and some U.S. Senate seats (roughly one-third), depending on the election year.
General election: The final election that determines officeholders, typically held in November, after parties have selected nominees.
Two contexts: presidential-year vs. midterm
Presidential-year general elections happen every four years, when Congress and the president are elected on the same ballot.
Midterm general elections occur halfway through a president’s term and elect Congress without a presidential contest at the top of the ticket.
Midterm election: A congressional general election held two years after a presidential election, during which all House seats and a portion of Senate seats are contested.
Presidential-year general elections (Congress + president)
Presidential-year elections tend to be more visible, more heavily covered, and more national in tone because the presidential race structures attention.
Turnout effects
Higher participation because voters are motivated by the presidency and then “roll down” to congressional races.
This chart plots reported U.S. voter turnout over time and visually shows the persistent turnout gap between presidential election years and midterm election years. It supports the idea that the presence of a presidential race typically broadens the electorate and increases participation. Source
A broader electorate often includes more infrequent voters, which can shift outcomes compared with midterms.
How outcomes can be shaped
Congressional candidates may benefit or suffer depending on how popular their party’s presidential nominee is.
Messaging is often coordinated informally around national party themes, encouraging more partisan voting across the ballot.
Coattail effect: When a strong candidate at the top of the ticket (often president) helps candidates from the same party win down-ballot races, including House and Senate seats.
Midterm general elections (Congress only)
Midterms function differently because there is no presidential contest to mobilise marginal voters, and voters often treat the election as a judgement on current national conditions.
Turnout effects
Lower overall turnout, meaning the electorate is typically older, more consistent, and more politically engaged than in presidential years.
Participation gaps can widen because less intense media attention and fewer high-salience cues reduce occasional voting.
How outcomes can be shaped
Voters may use midterms to reward or punish the president’s party, even though the president is not on the ballot.
Campaigns often emphasise national performance (economy, major events, major policies) rather than purely local concerns.
How election type shapes turnout and outcomes
The syllabus focus is that both election types are general elections for Congress, but their timing changes turnout and results.
The electorate is not the same electorate
Presidential years: larger and more diverse electorate; more low-propensity voters participate.
Midterms: smaller electorate; participation is more concentrated among high-propensity voters.
These shifts matter because parties can be advantaged by the composition of who shows up, not just by persuasion.
National mood and accountability cues
Election type changes what voters pay attention to:
Presidential years encourage comparisons between competing governing agendas.
Midterms encourage evaluation of the status quo, often tying congressional candidates to the sitting president’s perceived performance.
Governing consequences
Because Congress can change hands in either type of general election, election timing affects:
The president’s ability to pass legislation
Oversight intensity
The likelihood of split-party control between Congress and the presidency
FAQ
The Constitution sets two-year terms for House members to keep the chamber closely tied to public opinion.
This creates frequent national “checkpoints” on party control, regardless of the presidential cycle.
Only one-third of Senate seats are up each cycle, so the map can be more or less favourable in a given midterm.
This can make Senate outcomes diverge from national mood more than House outcomes.
Special elections can add or remove a few members between regular cycles.
They may signal national trends, but they do not replace the nationwide turnout and seat exposure of a true midterm.
House districts are smaller and uniformly contested, while Senate races are statewide and only some states vote each cycle.
Candidate quality and state partisanship can therefore matter differently across chambers.
Where available, straight-ticket mechanisms can increase party-line voting, especially when partisan cues are strong.
Its effect can vary by year depending on polarisation, campaign salience, and voter familiarity.
Practice Questions
(2 marks) Explain one way that turnout typically differs between presidential-year congressional general elections and midterm congressional general elections.
1 mark for identifying a valid difference (e.g. turnout is higher in presidential years than midterms).
1 mark for a brief explanation linking the difference to the presence/absence of the presidential contest or voter mobilisation.
(5 marks) Analyse how the type of congressional general election (presidential-year versus midterm) can shape election outcomes for House or Senate races.
1 mark for accurately describing presidential-year dynamics (higher turnout and more nationalised context).
1 mark for accurately describing midterm dynamics (lower turnout and “judgement” on the status quo).
1 mark for explaining how turnout composition can advantage/disadvantage a party.
1 mark for explaining a mechanism such as the coattail effect or referendum-style voting.
1 mark for a clear, election-outcome-focused link (seat gains/losses, party control, or competitiveness).
