In the 1972 case Rosario et al. v. Rockefeller, Governor of New York, et al., the U.S. Supreme Court upheld a New York law that required voters to enroll in a political party at least 30 days before the general election in November to be eligible to vote in the next primary elections (which could occur up to eleven months later). The plaintiffs argued this violated their First and Fourteenth Amendment rights by effectively excluding them from participating in primary elections if they missed this deadline or decided to change parties after it had passed. However, on appeal from a three-judge district court panel decision ruling against them, the Supreme Court held that these requirements served valid state interests - including preventing "party raiding" (where members of one party strategically register as members of another party for primaries) and encouraging voters' thoughtful choice about their partisan affiliation - without unduly burdening potential new registrants' right to vote.

In the dissenting opinion for Rosario v. Rockefeller, Justice Marshall argued that New York's voting laws were unconstitutional because they disenfranchised a significant number of voters who failed to meet the state's early enrollment deadline. He believed that these laws disproportionately affected minority and low-income communities, as well as those with less education or political awareness. The justice also pointed out that many other states had more lenient deadlines without any negative effects on their electoral processes. Furthermore, he criticized the majority for failing to adequately consider whether there was a compelling state interest in maintaining such restrictive voting regulations. In his view, promoting party stability did not justify denying citizens their fundamental right to vote.