Question: can you vote for both parties in an open primary

Answer: No, An open primary is a primary election that does not require voters to be affiliated with a political party in order to vote for partisan candidates. In a traditional open primary, voters may select one party's ballot and vote for that party's nomination. As in a closed primary, the highest voted candidate in each party then proceeds to the general election. In a nonpartisan blanket primary, all candidates appear on the same ballot and the two highest voted candidates proceed to the runoff election, regardless of party affiliation. The constitutionality of this system was affirmed by the Supreme Court of the United States in 2008, whereas a partisan blanket primary was previously ruled to be unconstitutional in 2000. The arguments for open primaries are that voters can make independent choices, building consensus that the electoral process is not splintered or undermined by the presence of multiple political parties.