What Happens If Trump Drops Out

  In case Trump were to drop out of the campaign, how would a new candidate be selected. Looks like this article answers the question, but the short answer would be the Republican National Committee makes the pick and votes on it.

Teaching History: Presidential Death (or Withdrawal) During The Election Process

The Party Chair calls a meeting of the National Committee, and the Committee members at the meeting vote to fill the vacancy on the ticket. A candidate must receive a majority of the votes to win the party's nod.