Marxism is not a system of government but a mode of thought; Stalinism, Leninism, Trotskyism, socialism, Third Way Socialism, are just interim steps toward the complete abolition of the state and the onset of the Workers Paradise. Indeed, Karl Marx recommended a period of "free trade" and high income taxes to ensure a large prosperous state; he then suggested this state would be imperialistic as it search for new markets, all the while he advocated a program of over turning traditional institutions like the family, marriage, church, gun rights, free press...
While Stalinism died with Stalin, though you could argue it lives in North Korea, Trotskyism had many adherents (James Burnham--a founder of National Review, Irving Kristol) who found their way into the upper echelon of the Republican Party in the 1980s. Indeed, National Review printed an indefense of Trotsky earlier this year by Stephen Schwartz.