Coattails and common sense  The term coattails is the most vivid
literary analogy in American politics, but also the most
deceptive. Coattails convey that because voters support the top
of the ticket, they will automatically hold on, voting for that
party’s down ballot candidates. Yet that is not how it works: 
coattails are a function of grassroots turnout, not a top down
down phenomenon.   Coattails come into play, when the top of the
ticket draws either new voters to the polls, or pulls voters
away from prior partisan loyalties. Eisenhower in 1956 and Nixon
in 1972, despite huge landslides, had no coattails. Their
victories were premised upon sponging up Democratic votes, not
transforming the underlying balance of electoral power. Yet,
Reagan in 1980 and Obama in 2008, with lesser margins, generated
coattails.  Under Reagan the GOP expanded the entrance of
Evangelical voters to the electorate and largely severed White
Catholic loyalties to the Democrats.  Obama’s coattails were
premised upon a double play: