A more thorough explanation:

Definition: The swing vote is the deciding vote in an election or decision-making process when all other votes are evenly split.

Example: In a presidential election, if the two candidates receive an equal number of electoral votes, the swing vote of a single state could determine the outcome of the election.

Explanation: The swing vote is crucial in situations where there is a tie or an even split in the voting process. It can be the deciding factor in determining the outcome of an election or a decision. In the example given, the swing vote of a single state can determine the winner of the presidential election, making it a very important vote.