Let's focus on the Domino Theory since we are also discussing the "Iron Curtain" speech above. The myth at the time was that all communist regimes throughout the world, whether the USSR, China, Cuba, or Vietnam were part of the same global movement for communist domination. As years go on, Nixon's visit to China would dispel that myth as would the 1979 Sino-Vietnamese war between Vietnam, Cambodia, and China (three communist states). At the time, was the Domino Theory an accurate theory to follow?

Please a somewhat short answer with a cited reference. Do not copy your response from somewhere else and I prefer not to have a three page answer although your help is greatly appreciated.