The 175th New York State Legislature, consisting of the New York State Senate and the New York State Assembly, met from January 6 to June 23, 1965, during the seventh year of Nelson Rockefeller's governorship, in Albany.

Under the provisions of the New York Constitution of 1938, re-apportioned in 1953, 58 Senators and 150 assemblymen were elected in single-seat districts for two-year terms. The senatorial districts consisted either of one or more entire counties; or a contiguous area within a single county. The counties which were divided into more than one senatorial district were Kings (nine districts), New York (six), Queens (five), Bronx (four), Erie (three), Nassau (three), Westchester (three), Monroe (two) and Onondaga (two). The Assembly districts consisted either of a single entire county (except Hamilton Co.), or of contiguous area within one county.

In 1964, the U.S. Supreme Court handed down several decisions establishing that State legislatures should follow the One man, one vote rule to apportion their election districts. A special Federal Statutory Court declared the New York apportionment formulae for both the State Senate and the State Assembly unconstitutional, and the State Legislature was ordered to re-apportion the seats by April 1, 1965. The court also ruled that the 1964 legislative election should be held under the 1954 apportionment, but those elected could serve only for one year (in 1965), and an election under the new apportionment should be held in November 1965. Senators John H. Hughes and Lawrence M. Rulison (both Rep.) questioned the authority of the federal court to shorten the term of the 1964 electees, alleging excessive costs for the additional election in an off-year.

At this time there were two major political parties: the Democratic Party and the Republican Party. The Liberal Party, the Conservative Party, the Socialist Labor Party, and the Socialist Workers Party also nominated tickets. At the New York state election, 1964, on November 3, Democratic majorities were elected to both the State Senate and the State Assembly for the session of 1965.

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