Guevarism is a theory of communist revolution and a military strategy of guerrilla warfare associated with Argentinian Marxist Che Guevara. Guevara, one of the leaders of the Cuban Revolution, believed in the foco theory, which promoted exporting the revolution to any country supported by an imperialist nation (specifically the United States), claiming that popular forces will always defeat the government due to their advantage in a non-urban setting. He believed in vanguardism by small "commando" units instead of by parties, and he was inspired by Maoism's "protracted guerrilla war" theory and the Viet Cong's strategy during the Vietnam War. The theory was criticized by guerrillas such as Abraham Guillen, however, as he believed that cities were a better ground for "urban guerrillas", and he criticized Guevara's national liberation forces for trying to impose dictatorships instead of self-management.