It was not inevitable. From one perspective, there was significant debate among policy-makers in the United States about the degree to which the US should aid Chiang Kai-Shek. US aid was sporadic though considerable, but if the United States had invested more in the conflict, things could have gone differently. It seems unlikely that Mao's army and his movement could have been completely defeated, but certainly the civil war could have ended on different terms than it did. Either way, it stands as one of the great human tragedies in terms of lives lost.