What phenomenon does the coattail effect illustrate in elections?

The coattail effect illustrates the phenomenon where strong candidates, particularly those running for higher offices, can enhance the electoral chances of other candidates from the same political party who are running for lower-profile positions. When a popular candidate, often during a presidential election, attracts a large number of voters, those voters are likely to also support other candidates from the same party on the ballot. This effect can lead to increased victories for members of that party, particularly in legislative or local elections, as they benefit from the popularity and appeal of the higher-profile candidate.

This dynamic underscores the interconnectedness of elections within the same political party and highlights how the appeal of one candidate can influence the electorate's decisions regarding others, thereby implicating party unity and strength during elections.