Law and government
 
 A Critical Mass gathering on the Daley Plaza, with Chicago City Hall in the backgroundMain article: Law and government of Chicago
 See also: List of Chicago city departments and Political history of Chicago
 Chicago is the county seat of Cook County. The government of the City of Chicago is divided into executive and legislative branches. The Mayor of Chicago is the chief executive, elected by general election for a term of four years. The mayor appoints commissioners and other officials who oversee the various departments. In addition to the mayor, Chicago's two other citywide elected officials are the clerk and the treasurer.
 The City Council is the legislative branch and is made up of 50 aldermen, one elected from each ward in the city. The council enacts local ordinances and approves the city budget. Government priorities and activities are established in a budget ordinance usually adopted each November. The council takes official action through the passage of ordinances and resolutions.
 During much of the last half of the 19th century, Chicago's politics were dominated by a growing Democratic Party organization dominated by ethnic ward-heelers. During the 1880s and 1890s, Chicago had a powerful radical tradition with large and highly organized socialist, anarchist and labor organizations.64 For much of the 20th century, Chicago has been among the largest and most reliable Democratic strongholds in the United States, with Chicago's Democratic vote totals leading the state of Illinois to be "solid blue" in presidential elections since 1992. The citizens of Chicago have not elected a Republican mayor since 1927, when William Thompson was voted into office. The strength of the party in the city is partly a consequence of Illinois state politics, where the Republicans have come to represent the rural and farm concerns while the Democrats support urban issues such as Chicago's public school funding. Although Chicago includes less than 25% of the state's population, eight of Illinois' nineteen U.S. Representatives have part of the city in their districts.
 Former Chicago Mayor Richard J. Daley's mastery of machine politics preserved the Cook County Democratic Organization long after the demise of similar machines in other large U.S. cities.65 During much of that time, the city administration found opposition mainly from a liberal "independent" faction of the Democratic Party. The independents finally gained control of city government in 1983 with the election of Harold Washington. Since Washington's death, Chicago has since been under the leadership of Richard M. Daley, the son of Richard J. Daley. Because of the dominance of the Democratic Party in Chicago, the Democratic primary vote held in the spring is generally more significant than the general elections in November.