His son said that he died Friday at his home in New York.
Michael Krinsky, who worked with Rabinowitz and Leonard Boudin, told The New York Times that Rabinowitz argued before the U.S. Supreme Court in 1963 that U.S. courts couldn't question Cuba's nationalization of U.S. companies. Che Guevara made Rabinowitz and Boudin Cuba's U.S. lawyers after beating them at chess at a Havana hotel.
Rabinowitz represented Chile in a similar case that became moot when Chilean President Salvador Allende was ousted and killed in 1973.
A native of Brooklyn, Rabinowitz attended the University of Michigan and the Michigan law school. He went to work for Louis Boudin in 1938 and became his nephew's partner six years later. The partnership specialized in labor law and represented many left-wing unions.
Rabinowitz was a member of the Communist Party for about 20 years, leaving in the 1960s, the Times said. He was a founder of the National Lawyers' Guild.