This is known as the "battleground state effect," and it is based on the idea that in states where the outcome of the election is uncertain, voters are more likely to feel that their vote can make a difference. This can lead to increased voter engagement and turnout in these states compared to states where the outcome is more predictable. Researchers have found evidence to support this theory, with data showing higher voter turnout in battleground states in presidential elections. This effect highlights the importance of engaging voters and making them feel that their voices are heard in the democratic process.
