My thesis investigates how the openness of presidential primaries affects youth turnout in different states. Because primary systems are built by states, it may explain why turnout rates vary. Some states hold closed primaries in which only voters registered with the Democratic or Republican parties can participate. Some states hold semi-closed primaries in which voters registered as independents are able to vote in either the Democratic or Republican primary. Other states hold open primaries in which voters, no matter their party affiliation, may vote in any primary contest.