The United States operates as a constitutional federal republic with power divided among Congress, the president, and the federal judiciary. Authority is also shared with 50 state governments and thousands of local jurisdictions, including counties, municipalities, school districts, and special districts.
Most officials are elected directly, but presidents are chosen indirectly through the Electoral College. American elections are dominated by Democrats and Republicans, a result reinforced by single-member districts and plurality voting. Third parties rarely gain lasting influence.
The system has expanded suffrage over time, from property-owning white men to nearly all citizens aged 18 and older, though restrictions remain for some felons and residents of U.S. territories. Major debates now concern campaign money, unequal representation, gerrymandering, polarization, political distrust, and whether wealthy interests exert disproportionate influence. The enduring question is whether institutions built to restrain power still represent the people they govern.