The major political parties are organized at the local (usually county), state, and national levels. Party leaders and activists are involved in choosing people to run for office, managing and financing campaigns, and developing positions and policies that appeal to party constituents. The national party organizations play key roles in presidential elections.
Local party organization
Political parties operate at the local level in municipal and county elections (though many cities choose officials — mayors and members of city council — through nonpartisan elections, in which candidates effectively run as independents without party affiliation). In partisan elections, the party is involved in identifying candidates, providing professional staff, and taking positions on issues of immediate concern to voters. The party leadership recognizes that the interaction between party workers, candidates, and voters is important.
In the late 19th century on through a good part of the 20th century, political machines flourished in several large cities; Tammany Hall in New York, Frank Hague in Jersey City, the Pendergast family in Kansas City, and Richard Daley in Chicago are examples. The political bosses, the mayors, and the party leaders used their control of patronage jobs to reward party loyalty and provide a broad range of social services. Reforms in the civil service and the growth of primary elections gradually brought an end to machine politics.
State party organization
Political parties prepare for statewide elections. Party activists are named as electors in the Electoral College if their party carries the state in a presidential election. Candidates for state office may be chosen through a primary election, state convention, or caucus process. At a state caucus, party members select their candidates. In many states, the executive officials — governor, lieutenant governor, treasurer, and attorney general — are elected as individuals. Although the party's slate, its candidates for office, is listed on the ballot, voters can vote for any candidate they want. In such states, it is not unusual for voters to elect a Democratic governor and a Republican lieutenant governor or vice versa.
National party organization
At the national level, political parties run candidates for Congress and the presidency. Each party has its own national committee made up of party leaders, elected officials, and the chairs of the state party organizations. The chair of the national committee is chosen by the party's candidate for president. The Democratic and Republican national committees do not run the campaigns of their respective presidential candidates; they play a supporting role to the campaign organizations of the candidates themselves. In both the Senate and the House, each party has its own congressional campaign committee, which raises money for congressional elections.
The national convention
The national committee loosely runs the party between national conventions. As noted earlier, a party's choices for president and vice president are nominated at the national convention. The delegates to the convention are already committed to vote for particular candidates based on the results of the state primary or caucus voting. While some delegates are appointed by the state party organization, the overwhelming majority are selected through primaries and caucuses. A party's nominee is often determined months before the convention, which makes the choice official. The party works on and announces its platform at the national convention. The platform is made up of planks that explain how the party stands on the issues facing the country. The terms platform and plank date from the presidential election of 1832, when national party conventions were first held. Developing the platform is often the most controversial part of the convention. The Republicans, for example, have had to work out an acceptable compromise on abortion between pro-choice and pro-life forces within the party.