Defending the materialist foundations of scientific socialism, Leon Trotsky responds to the rising pressures of bourgeois public opinion on the middle classes during the buildup toward U.S. entry into World War II. He explains why working people must oppose imperialist assaults on the degenerated Soviet workers state. And why only a party that fights to bring growing numbers of workers into its ranks and leadership can chart a revolutionary course. Leon Trotsky was a central leader of the Russian revolution. Forced into exile by Joseph Stalin in 1929, he was murdered by an agent of Stalin in 1940. In Defense of Marxism is a companion volume to The Struggle for a Proletarian Party by U.S. communist leader James P. Cannon.