5.9 Congressional Elections

Q: How do casework and the franking privilege contribute to the incumbency advantage?

Casework involves staff helping constituents solve problems with federal agencies, building personal loyalty, while the franking privilege allows members to send free mail to constituents to maintain high visibility.

Q: What is the difference between apportionment and redistricting?

Apportionment is the process of dividing the 435 House seats among states based on Census population, while redistricting is the redrawing of district boundaries within a state by state legislatures.

Q: What was the significance of the Supreme Court case Baker v. Carr (1962)?

Baker v. Carr established the "one person, one vote" principle and ruled that redistricting challenges are justiciable , meaning federal courts have the authority to hear cases regarding legislative redistricting.

Q: Why does the President's party typically lose seats in midterm elections?

This happens due to lower voter turnout (often among those satisfied with the status quo), voter anger directed at the incumbent President, and the disappearance of the "coattail effect."

Q: How has professionalization changed modern Congressional campaigns?

Modern campaigns rely heavily on political consultants , social media for direct voter engagement, and massive fundraising efforts to pay for expensive media and digital advertising.

Q: What is the primary difference between the election cycles of the House and the Senate?

All 435 House members are up for election every 2 years, while only one-third of the Senate is up for election every 2 years due to their staggered 6-year terms.

AP United States Government and Politics · AP (Advanced Placement) · 5 min read · Updated: 7 Sept 2026

Welcome to Chapter 5.9: Congressional Elections!

While the race for the White House gets most of the media attention, the elections for the House of Representatives and the Senate are where the day-to-day power to make laws is decided. In this chapter, we will explore why it is so hard to beat someone already in office, how lines on a map can change an election, and why the President’s party usually has a "bad day" during midterms. Don't worry if these terms seem a bit dense at first—we'll break them down step-by-step!

1. The Power of the Incumbent

In a Congressional election, the single most important factor is often whether or not a candidate is an incumbent. An incumbent is a person who already holds the office and is running for re-election. In the United States, incumbents win their races at a very high rate—often over \(90\%\) in the House of Representatives!

Why do Incumbents usually win?

Name Recognition: Voters are much more likely to vote for a name they have seen on the news or on local signs for years.
Casework: Members of Congress have staff dedicated to helping constituents (the people they represent) solve problems with government agencies, like tracking down a missing Social Security check. This creates very loyal voters!
The Franking Privilege: Members of Congress can send mail to their constituents for free to keep them informed. While they can't use it for campaign ads, it is a great way to keep their name in front of voters.
Fundraising Advantage: Donors and Political Action Committees (PACs) usually give more money to incumbents because they are "safe bets" who already have power.

Quick Review: Think of an incumbent like a defending champion in sports. They have the home-field advantage, the best equipment, and the fans already know their name. The "challenger" has to work twice as hard just to get noticed!

2. The Rules of the Game: Districts and Lines

Every ten years, the U.S. Census counts the population. Based on those numbers, states might gain or lose seats in the House (this is called apportionment). Then, state legislatures must redraw the district boundaries (this is called redistricting).

Gerrymandering

Gerrymandering is when district lines are drawn in weird shapes to give one political party a massive advantage. By "packing" opposition voters into one district or "cracking" them across many districts, the party in power can ensure they win more seats than they probably should based on the total popular vote.

Essential SCOTUS Cases

You must know these two cases for the AP Exam regarding how districts are drawn:

Baker v. Carr (1962): This case established the principle of "one person, one vote." The Court ruled that redistricting challenges can be heard by federal courts. It ensured that districts must be roughly equal in population so that one person's vote isn't "worth more" than another's.
Shaw v. Reno (1993): This case dealt with racial gerrymandering. The Court ruled that while creating districts to help minorities is sometimes allowed, a district cannot be drawn based only on race if it results in a shape so bizarre that it ignores all other logical factors. This falls under the Equal Protection Clause of the 14th Amendment.

3. Midterm vs. Presidential Elections

Not all Congressional elections happen at the same time. While some happen during a Presidential election year, others happen at the two-year mark of a President's term. These are called midterm elections.

The Midterm Effect

History shows a very consistent pattern: The President's party almost always loses seats in Congress during midterm elections.

Why does this happen?
1. Voter Turnout: Turnout is much lower in midterms. The people who do show up are often the ones who are angry with the current President.
2. The "Coattail Effect" Ends: During a Presidential year, a popular President might help other members of their party get elected (carrying them in on their "coattails"). In midterms, that boost is gone.

Did you know? Since World War II, the President's party has lost seats in the House in almost every single midterm election. It is one of the most predictable trends in American politics!

4. Modern Campaigning and Professionalism

Congressional elections have become incredibly expensive and professionalized. Gone are the days of just shaking hands at a local diner. Today, candidates rely on:

Political Consultants: Professionals who specialize in polling, media, and "attack ads."
Social Media: Used to bypass traditional news and speak directly to voters (and to ask for small-dollar donations).
Rising Costs: Because of the high cost of TV and digital ads, candidates spend a massive amount of their time fundraising rather than legislating.

Note: For more on how these campaigns are paid for, check out Chapter 5.11 on Campaign Finance!

Key Takeaways for the Exam

1. Incumbency is King: Most members of Congress stay in Congress because of the resources and recognition they have.
2. Geography Matters: How districts are drawn (Redistricting/Gerrymandering) determines which party has the advantage before a single vote is cast.
3. The Courts Intervene: Remember Baker v. Carr (1962) for population equality and Shaw v. Reno (1993) for limits on racial gerrymandering.
4. Midterms are Tough: The party in the White House usually loses ground in the House and Senate during the middle of a President's term.

Common Mistake to Avoid: Don't confuse the House and the Senate election cycles! All \(435\) members of the House are up for election every \(2\) years. In the Senate, only \(1/3\) of the seats are up for election every \(2\) years (because Senators serve \(6\)-year terms). This makes the Senate more "stable" than the House.

Quick check

Can you answer these now?

Open each question to check the key ideas from this chapter.

What is an incumbent and what is their typical success rate in the House of Representatives?

An incumbent is an individual who currently holds a political office and is seeking re-election. In the U.S. House of Representatives, incumbents typically win re-election at a rate of over \(90\%\).

How do casework and the franking privilege contribute to the incumbency advantage?

Casework involves staff helping constituents solve problems with federal agencies, building personal loyalty, while the franking privilege allows members to send free mail to constituents to maintain high visibility.

What is the difference between apportionment and redistricting?

Apportionment is the process of dividing the 435 House seats among states based on Census population, while redistricting is the redrawing of district boundaries within a state by state legislatures.

What is gerrymandering and what are the two primary methods used?

Gerrymandering is drawing district lines to favor one party or group. The two main methods are "packing" (concentrating opposition voters in one district) and "cracking" (spreading opposition voters across many districts to dilute their power).

What was the significance of the Supreme Court case Baker v. Carr (1962)?

Baker v. Carr established the "one person, one vote" principle and ruled that redistricting challenges are justiciable, meaning federal courts have the authority to hear cases regarding legislative redistricting.

How did Shaw v. Reno (1993) impact racial gerrymandering?

The Court ruled that while race can be a factor in redistricting, districts cannot be drawn solely based on race if they result in bizarre shapes that ignore traditional redistricting principles.

Why does the President's party typically lose seats in midterm elections?

This happens due to lower voter turnout (often among those satisfied with the status quo), voter anger directed at the incumbent President, and the disappearance of the "coattail effect."

How has professionalization changed modern Congressional campaigns?

Modern campaigns rely heavily on political consultants, social media for direct voter engagement, and massive fundraising efforts to pay for expensive media and digital advertising.

What is the primary difference between the election cycles of the House and the Senate?

All 435 House members are up for election every 2 years, while only one-third of the Senate is up for election every 2 years due to their staggered 6-year terms.

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