Political Parties & Party Structure

An organized group of people who share broadly similar political values and goals and work together to elect candidates to public office and influence government policy. Political parties recruit and support candidates, develop policy platforms, mobilize voters, and provide an organizational infrastructure for political activity. In the United States, the Democratic and Republican parties have dominated national politics since the Civil War era, though third parties and independent candidates play a meaningful role in some elections and have historically been the source of policy ideas that the major parties later adopted.

Any political party other than the two major parties, the Democrats and the Republicans. Third parties in the United States face significant structural barriers to electoral success, including winner-take-all voting rules that favor established parties, ballot access requirements that make it difficult and expensive to qualify for the ballot in many states, exclusion from major debates, and limited access to campaign financing infrastructure. Despite these barriers, third parties have occasionally won elections at the local and state level and have influenced national politics by raising issues that the major parties later adopted.

A candidate who runs for office without the formal affiliation or support of a political party. Independent candidates may hold strong political views but choose not to align with an existing party, or they may run in nonpartisan elections where party labels do not appear on the ballot. Running as an independent presents many of the same structural challenges as running as a third-party candidate, including ballot access hurdles and limited access to party infrastructure, fundraising networks, and voter mobilization resources.

The official statement of a political party's positions, values, and policy goals, adopted at the party convention. The platform represents what the party collectively stands for and what it intends to pursue if its candidates are elected, though individual candidates are not legally bound to follow it. Party platforms are developed through a committee process involving delegates and party activists and can be a source of significant internal debate about the direction of the party.

A voter's formal or informal alignment with a political party. In states with party registration, voters declare a party affiliation when they register to vote, which may affect which primaries they can participate in. In states without party registration, voters may still identify with a party without formally declaring an affiliation. Party affiliation is one of the strongest predictors of voting behavior, though rates of self-identified independents have grown in recent decades as partisan polarization has increased dissatisfaction with both major parties.

An election in which registered members of a political party, or in open primary states any registered voter, choose the party's nominee for a general election. Party primaries replaced the older system of party bosses selecting nominees in closed-door meetings and were intended to give rank-and-file voters more power over the nomination process. The rules governing party primaries, including who can vote in them and how delegates are allocated, are set by a combination of state law and party rules.

A meeting of party members at the local, state, or national level to discuss party business, choose delegates, or make decisions about candidates and policy. In the context of presidential nominations, caucuses are an alternative to primaries in which voters gather in person, divide into groups supporting different candidates, and through a process of discussion and realignment determine how delegates are allocated. Caucuses have been criticized for their low participation rates and the barriers they create for voters who cannot attend in person, and several states have replaced their caucus systems with primaries in recent years.

A formal gathering of party delegates held at the state or national level for the purpose of nominating candidates, adopting the party platform, and conducting official party business. National conventions are held every four years to formally nominate the presidential and vice presidential candidates and are major televised political events. State conventions are held on varying schedules and may nominate candidates for statewide offices, select delegates to the national convention, elect party officers, and adopt state party platforms.

A candidate who is not listed on the printed ballot but whose name is written in by voters. Most states permit write-in voting, though the rules for whether write-in votes are counted and under what circumstances a write-in candidate can win vary. In some states, candidates must register as write-in candidates in advance for their votes to be counted. Write-in campaigns are occasionally successful in local elections but are exceedingly rare as a winning strategy in state or federal races.

An electoral practice in which a candidate appears on the ballot as the nominee of more than one political party simultaneously, with votes from all party lines tallied together. Fusion voting allows minor parties to support major-party candidates they endorse while maintaining their own ballot line, giving them leverage to influence policy and building their own electoral infrastructure. Once common in the United States, fusion voting was effectively eliminated in most states by laws passed in the late 19th and early 20th centuries. It remains legal and practiced in New York, where minor parties like the Working Families Party and the Conservative Party regularly cross-endorse major-party candidates.

An electoral system in which the share of seats a party receives in a legislature is roughly proportional to the share of votes it received. Proportional representation is used in many democracies around the world and tends to support the viability of multiple parties because votes for smaller parties are not wasted in the way they are under winner-take-all systems. It is not used in any U.S. federal elections, though it is occasionally discussed as a potential reform that could create more competitive and representative legislative bodies.

A term used to describe the dominance of American politics by two major parties, the Democrats and the Republicans, to the near-exclusion of third parties and independent political movements. The political duopoly is reinforced by structural features of the electoral system, including plurality voting, winner-take-all districts, campaign finance rules, debate qualification thresholds, and ballot access laws that collectively make it very difficult for parties outside the two-party system to gain and hold electoral power. Critics argue the duopoly limits voter choice and reduces accountability, while defenders argue the two-party system produces stable governance and clear electoral choices.

The legal requirements a candidate or political party must meet in order to appear on an official election ballot. Ballot access requirements vary significantly by state and by office and can include filing fees, nominating petitions requiring a specified number of voter signatures, party registration thresholds, and filing deadlines. Major party candidates typically face much lower ballot access hurdles than third-party candidates and independents, a disparity that critics argue unfairly advantages the two major parties and limits voter choice.

The process of collecting voter signatures on a nominating petition to qualify a candidate or ballot measure for the ballot. Signature gathering is a core activity for third-party candidates, independent candidates, and ballot initiative campaigns, which typically face more significant petition requirements than major-party candidates. Effective signature gathering requires significant volunteer or paid labor, careful compliance with state rules about who can circulate petitions and how they must be completed, and thorough verification before submission.

A political party that has some formal organization and ballot presence but does not have the electoral strength of a major party. Minor parties in the United States include the Green Party, the Libertarian Party, and various regional or state-level parties. Some minor parties focus on a specific issue or ideological position and measure their success less by winning elections than by influencing the policy positions of larger parties or building a long-term organizational base. The line between a minor party and a major party is not fixed and has shifted at several points in U.S. history.