The takeover of China by the Communists in 1949 added a new geopolitical concern to the interests of the United States in the Far East. Two theories of strategic concern were the Domino effect of potential Communist takeover of countries near to China’s mainland, and the Leapfrog theory, where it was considered the Communists might try to gain control of a country within the protected geographic sphere, and deemed a protectorate or ally of the Unites States. Of considerable concern was the potential threat to Indonesia.