In states that hold primary elections, voters choose their party’s nominees to run in the general election by casting ballots. Pennsylvania holds closed primary elections, meaning you must be a member of the party to vote for that party’s candidate (for example, you could not vote in the Republican primary unless you are a registered member of the Republican Party). Other states hold open primaries, in which you are allowed to vote for a candidate outside of your own party. Primary elections in Pennsylvania are held on the third Tuesday of May in all years except Presidential years, when it is held on the fourth Tuesday of April. To learn more about the difference between a primary and a caucus, read about caucuses on the Political Parties page.