Swing states, also known as battleground states, are crucial in U.S. presidential elections due to their ability to switch parties. These states do not consistently vote for one particular party and can influence the election outcome. The 2020 election saw several swing states, including Pennsylvania, Wisconsin, Michigan, and Arizona, decide the presidency. Swing states typically have large populations and diverse demographics, making them competitive. Candidates invest significant resources in campaigning in these states to win their electoral votes.