What is meant by "presidential coattails"?

The term "presidential coattails" refers specifically to the phenomenon in which a popular presidential candidate carries their party's congressional candidates to victory in elections. This occurs when voters who support the presidential candidate also extend their support to the candidates running for the House and Senate from the same party, effectively boosting their chances of winning due to the popularity and appeal of the presidential candidate at the top of the ticket.

This concept is significant because it highlights how the popularity of a presidential candidate can have a ripple effect on elections down the ballot, enhancing the overall prospects of that party in congressional races. It emphasizes the interconnectedness of presidential and congressional elections within the political landscape.

The other options do not accurately describe "presidential coattails." For instance, serving multiple terms, appointing cabinet members, and the tendency of presidents to campaign for themselves encompass different aspects of presidential responsibilities and political behavior that are unrelated to the specific effect of a presidential candidate's popularity on other electoral races.