https://www.city-journal.org/the-problem-with-new-yorks-closed-primary-system
We may see an outbreak of democracy in New York, thanks to the Court of Appeals’ decision to throw out state Democrats’ gerrymandered congressional district map. But while the shotgun marriages between Staten Island and Park Slope and between Westchester and Suffolk Counties have been called off, New York still has a long way to go before its elections are truly democratic. That’s because the Empire State remains one of only nine states with completely closed primary elections.
It may sound fair and logical to permit only registered Democrats or Republicans to vote in their respective parties’ primary elections, but in practice this limits voter choice and selects for candidates whose views tend to their party’s extreme wing. Closed primaries also mean that independents—those not enrolled in either party—are the most clearly excluded voters. New York now has more unaffiliated voters (2.75 million) than enrolled Republicans (2.74 million).
Voters who want to join a party or switch parties to have a say in a contested primary are out of luck. One can’t simply walk up and switch party affiliation on primary election day. New York election law requires such changes to be made by February 15, more than four months before the primary. That’s well before the campaign begins in earnest and the views of candidates become clear. It can even be before we know who will be on the ballot, as in the case of disgraced former lieutenant governor Brian Benjamin.