An American presidential election is won on a state-by-state basis An American presidential election is won on a state-by-state basis. Each state has a certain number of electoral votes, based on the number of seats the state has in the lower federal house, the House of Representatives, plus two (because each state has two senators). Representation in the lower house is decided by population. For example, Ohio, with a population of 11.5 million, has 20 electoral votes - 18 congressional districts plus two seats in the Senate. Wyoming, population 520,000, has three - one congressional district plus two Senate seats. Add them all up and the total comes to 538 electoral votes. A majority of 538 - half plus one - is 270, and that's what a candidate needs to win.