Decolonization in the world was contrasted by the Soviet Union's successful post-war expansionism. Tuva and several regional states in Eastern Europe, the Baltic, and Central Asia had been fully annexed by the Soviet Union during World War II. Now, it extended its influence by establishing the satellite states of Eastern Germany and the countries of Eastern Europe, along with support for revolutionary movements in China and North Korea. Although satellite states were independent and possessed sovereignty, the Soviet Union violated principles of self-determination by suppressing the Hungarian revolution of 1956 and the Prague Spring Czechoslovak reforms of 1968. It invaded Afghanistan to support a communist government assailed by local tribal groups. However, Marxism–Leninism and its theory of imperialism were also strong influences in the national emancipation movements of Third World nations rebelling against colonial or puppet regimes. In many Third World countries, communism became an ideology that united groups to oppose imperialism or colonization.