battleground state

In United States politics, a battleground state, also known as a swing state, is a U.S. state where both the Democratic and Republican parties have similar levels of voter support, making election contests highly competitive. These states are contrasted with "safe states" where voters consistently favor one party.1

In most U.S. presidential elections, the candidate who wins the popular vote in a state receives all of that state's Electoral College votes. Therefore, a candidate can win the presidency with a narrow popular majority in a few battleground states, even if they have a larger majority in safe states. Consequently, presidential candidates concentrate their campaign efforts and resources on battleground states, addressing issues pertinent to the residents of those areas. The term "battleground state" has been in use since at least the mid-19th century, referring to politically divided states that are likely to determine the outcome of a close election.12