Hal Draper (1914-1990) was another American Marxist who upheld Third Camp politics. Draper joined the socialist movement in 1932, becoming a national organiser of the Young People's Socialist League, the youth group associated with the Socialist Party. He became a Trotskyist and was a founder member of the SWP-USA in 1938.
In the 1939-40 split Draper sided with Shachtman. During the Second World War he worked in the shipyards in Los Angeles, helping to organise wildcat strikes.

After the war, and especially in the 1950s, Draper became a leading writer for the Workers Party and the Independent Socialist League, eventually producing the ISL paper Labor Action almost single-handed. He distanced himself from Shachtman after 1958, writing, for example, a stinging attack on Shachtman's support for the US-backed Bay of Pigs invasion of Cuba in April 1961.

He formed a group called the Independent Socialist Club, but after 1971 he withdrew from active politics and turned to writing scholarly works, notably the five-volume "Karl Marx's Theory of Revolution".