coat·tail 
(kōttāl′)
(kōttāl′)n.
Idiom: 1. The loose back part of a coat that hangs below the waist.
2. coattails The skirts of a formal or dress coat.
on the coattails of
1. As a result of the success of another: elected to office on the coattails of a popular governor.
2. Immediately following or as a direct result of: resigned on the coattails of the scandal.