 This led to the People's Republic of Albania withdrawing from the Warsaw Pact, briefly aligning with Mao Zedong's China until the Sino-Albanian split.Under the Brezhnev Doctrine, the Soviet Union reserved the right to intervene in other socialist states.In response, China moved towards the United States following the Sino-Soviet border conflict and later reformed and liberalized its economy while the Eastern Bloc saw the Era of Stagnation in comparison with the capitalist First World.