How the Two Major Parties Work: Committees, Conventions, and Platforms
Key takeaways
- The Constitution does not mention political parties, but the Democrats, organized in the 1820s and 1830s, and the Republicans, founded in 1854, have dominated since the 1850s.
- Each party is run by a national committee, the DNC since 1848 and the RNC since 1856, that sets nominating rules and runs the national convention.
- Four Hill committees, the DCCC, NRCC, DSCC, and NRSC, recruit and fund candidates for Congress.
- Platforms are adopted at each convention but do not bind candidates.
- A 2026 Supreme Court ruling lifted limits on how much parties can spend in coordination with their candidates.
- Most party work happens through about 3,000 county parties and 50 state parties, each governed partly by state law.
Parties organize nearly everything in American politics, from who appears on ballots to how Congress runs, yet they are loose coalitions with many centers of power. Voters, activists, officeholders, donors, and party officials all compete to shape them.
This guide explains how the two major parties are structured and how they work. Third parties, primaries, and campaign finance have their own guides.
In Congress, each party's members form a caucus or conference that elects leaders, assigns committee seats, and sets strategy. Four Hill committees, two for each party in each chamber, recruit candidates, decide which races to target, and spend hundreds of millions of dollars each cycle, funded partly by dues from members of Congress.
The Democratic National Committee, founded in 1848, has about 450 members, and the Republican National Committee, founded in 1856, has 168, three from each state and territory. Each elects a chair, raises money, maintains voter data, sanctions debates, and writes or proposes rules for choosing the presidential nominee. When a party holds the White House, the President usually has strong influence over its committee.
Every four years each party holds a national convention where delegates, mostly chosen in primaries and caucuses, formally nominate the presidential and vice presidential candidates, adopt rules, and approve a platform stating the party's positions. Platforms are not binding, but parties carry out many of their promises when they win power. Conventions now mostly ratify the primary results and serve as televised kickoffs for the general election.
Parties can receive larger contributions than candidates and must disclose their donors. Since 2010, super PACs and other outside groups that can raise unlimited sums have rivaled the parties in spending. In 2026 the Supreme Court, in NRSC v. FEC, struck down limits on how much parties can spend in coordination with their own candidates, a change supporters say strengthens accountable parties and critics say helps big donors avoid limits.
A political party brings together voters, activists, and officeholders who share broad goals, and seeks to win elections and govern. The Constitution's framers distrusted factions, but parties formed within a decade. The Democratic Party traces its roots to the 1820s and 1830s, and the Republican Party was founded in 1854. Because most states award elections by plurality in single-member districts, the two parties have dominated since the 1850s.
State and county parties recruit local candidates, run conventions and some primaries, and organize volunteers, under state laws that set how parties choose nominees and get on the ballot. Some say parties have grown too weak, as primaries, social media, and outside money let candidates bypass party leaders. Others say parties have become too polarized and too powerful over ballot access, and favor open primaries, ranked-choice voting, or other reforms.
See minor parties in third parties explained, nominations in how primaries and caucuses work, or money in campaign finance explained.