State and local policy. Military and overseas voters can participate in an election and its corresponding runoff at once, preventing them from being disenfranchised when two elections do not allow sufficient time for ballots to be mailed and returned.
State policy. By the time military voters have received, filled out, and mailed back their ballots in presidential nominating contests, one or more candidates may have dropped out of the race. By allowing them to use ranked ballots, they can ensure that their vote will count for their favorite candidate that is still in the running.