Vander Plaats led the fight against gay marriage in Iowa, helping to remove a number of the state's Supreme Court justices who ruled that gay marriage must be legal in the state. He has a lot of influence with the state's large Christian conservative population — Vander Plaats's endorsements helped both Arkansas Gov. Mike Huckabee (R) and former Sen. Rick Santorum (R-Pa.) win the Iowa caucuses in recent years.

Christie's decision to withdraw an appeal of a court ruling legalizing gay marriage could hurt him in Iowa, though if he runs for president that has never been a state he's been expected to do well in. The move could hurt him with social conservatives in other early-voting states, however.