S3: The factors making the invasion of Korea both tenable and appealing vary widely.  Primarily the geography of the northeast Asia lends itself to making Korea a focal point in the region.  It provides easy access to the north of the peninsula for the natural resources found in the Manchurian region.  Also due to its proximity to both the northeast Chinese coast and the western coasts of the Japanese islands make it fulcrum for naval supremacy in this region.  Additionally due to decades of brutal Japanese occupation finally coming to an end after the second world war the Korean military was a largely understrength and undersupplied force in the 1950s, the United States knew this and reinforced the region knowing full well it would be their only anchor point on the northern part of the Asian continent.  The duality between the spread of Communism and Democracy meant that in order to exert regional hegemony over the area communist forces (both Russian and Chinese backed) had to drive out this democratic foothold on the peninsula.  This made the invasion of Korea an absolute necessity for Communist regimes.