Justin N. Feldman, a Manhattan lawyer who helped manage Robert F. Kennedy’s 1964 New York Senate campaign and whose deep involvement in city politics extended from the 1940s, when he joined with other reform Democrats to oppose Tammany Hall, through the 1980s, when he helped broker a $5.6 billion rebuilding program for the city’s public transportation system, died Wednesday at his home in Manhattan. He was 92. The cause was congestive heart failure, according to his wife, Linda Fairstein, the former sex-crimes prosecutor and crime novelist.

Feldman, a liberal Democrat who was later a campaign aide for John F. Kennedy, entered reform politics in the late 1940s as a leader of the Fair Deal Democratic Club. The group was dedicated to breaking the political influence of Tammany Hall, whose machinations Feldman analyzed trenchantly in an influential article, “How Tammany Holds Power,” published in the journal National Municipal Review in 1950.

He ran as a Fair Deal candidate for the post of Manhattan Borough president in 1949 before withdrawing in favor of the eventual winner, the liberal candidate Robert F. Wagner Jr. In 1960, Feldman managed William F. Ryan to a stunning upset over the Tammany-backed candidate in the 1960 election for the House of Representatives from New York’s 20th Congressional District, then on Manhattan’s West Side.

“Justin Feldman was a reformer before reform in Democratic politics became popular,” former Mayor Edward I. Koch, an old comrade in arms of Feldman’s, said in an e-mail Friday.

As chairman of the law committee of the Manhattan Democratic Committee, Feldman challenged the constitutionality of the 1961 statute that redrew Manhattan’s four congressional districts, arguing, in a case that reached the U.S. Supreme Court, that the boundaries created racial enclaves.

Especially glaring were the 17th Congressional District on the East Side, known as the Silk Stocking District, then represented by John V. Lindsay, and the 18th District on the Upper East Side and East Harlem, represented by Adam Clayton Powell Jr. The 17th District excluded 97 percent of Manhattan’s nonwhite residents; the 18th District excluded 99.5 percent of its white residents.

Arguing before the Supreme Court in Yvette M. Wright et al. v. Nelson A. Rockefeller, Feldman said of the redistricting, “It hurts the Negroes because it puts all their influence in one district and denies them the ability to influence congressional elections in other districts.”

Asked by Justice John Marshall Harlan II, “If you started out to construct a segregated congressional district, could you do a better job than this?” Feldman answered, “It would be absolutely impossible.”

On Feb. 17, 1964, the court ruled 7-2 that the plaintiffs had failed to prove racial discrimination.