Swing states, also known as battleground states, are states that could “swing” to either Democratic or Republican candidates depending on the election. Because of their potential to go either "blue" or "red", political parties often spend a disproportionate amount of time and campaign resources on winning these states.
While there is no universal definition of what identifies a swing state, they are characterized by having small vote margins and that different political parties win over time. Since 1992, 30 states have voted for the candidate of the opposite party from the previous election at least once. And 26 states were won by less than three points in any presidential election since 1992.
