In the United States, elections occur every two years (in what are called midterm elections) and every four years for the presidential race, following a federalist system where the organization is divided between the federal government and state governments. This model leads to variations in voting rules from state to state, but within the general guidelines established by the Constitution and federal law. This structure reflects the diversity and autonomy of the states while maintaining a common foundation to ensure fairness and representativeness in the electoral process.

To be eligible to vote in the United States, a citizen must meet certain requirements. They must be an American citizen, either naturalized or born in the country, be at least 18 years old on election day, and be registered to vote. Voter registration is mandatory in almost all states and must be completed by specific deadlines before the election. Some states impose restrictions on certain categories of citizens, such as ex-felons, depending on the state and the severity of the offense.

Voter registration is a prerequisite in nearly every state, and the process can be completed in person, online (where allowed), or by mail. Registration must be done in advance to ensure participation in the desired election, serving as a key element in ensuring that only eligible voters can vote, thus upholding the integrity of the electoral system.

The United States offers three main methods of voting. In-person voting takes place at designated locations on election day, and some states allow voters to cast their ballots in person ahead of time. There is also the option of voting by mail, available in all states, though with varying regulations: in some states, ballots are automatically sent to registered voters, while in others, they must be requested. Finally, many states offer early voting, which allows voters to participate within a predefined period, making voting more accessible.

For presidential elections, the country uses the Electoral College system, in which each state has a number of delegates proportional to its population, with a minimum of three delegates, corresponding to its representatives in the House and the Senate. To win, a presidential candidate must secure at least 270 of the 538 Electoral College votes, reflecting both the population and geographic representation of the states in the choice of president.

Eligibility for federal offices, such as the presidency or vice presidency, requires candidates to meet certain criteria: they must be at least 35 years old, be a natural-born American citizen, and have resided in the country for at least 14 years. These requirements are intended to ensure that candidates have a strong connection to the country and are qualified to represent it, maintaining accountability and commitment to national values and interests.