In an op-ed in the Gotham Gazette, SAM Party of New York Chairman Michael Volpe describes why open primaries are desperately needed in New York:

In a democracy, residents are supposed to choose their elected officials. In New York, politicians from both the Republican and Democratic parties have worked hard to turn that idea on its head and pick their constituents. New York’s ballot access rules are among the most restrictive in the nation and the results speak for themselves -- apathetic voters who can’t be bothered to engage in a system that makes it hard to participate and where they do not feel that their vote really matters. 

Open primaries allow all registered voters to vote in a primary where all candidates for office are grouped together regardless of party affiliation. If no candidate receives 50% of the vote, the top two then face off in a general election, even if they are from the same party. It’s a system based on encouraging democracy.

Open primaries also allow new candidates from nontraditional backgrounds to break into the system. In the current structure, voters often avoid casting a ballot for candidates outside of the traditional parties for fear of spoiling the election in favor of someone they truly dislike. Traditional parties have intentionally perpetuated this dilemma to keep new players out and keep a broken system and the privileges that come with it in place.