The Soviet Union’s hope for the spread of communism and communist supremacy throughout the world was obvious; it gained control of North Korea after the end of Japan’s Imperialist rule with the end of the Second World War. Stalin had Mao as a new ally with China’s conversion to communism in 1950, and this brought to him a great advantage. The Sino-Soviet Treaty in 1950 ensured that along with gaining a communist neighbor, Stalin could be given support by the Chinese in the form of supplies, tactics and troops if he decided to invade South Korea in the hopes of spreading communism further. The victory of the CCP in China provided the USSR with battle hardened Chinese soldiers, which only encouraged him further. The eagerness of Stalin (as well as Kim Il Sung) to expand communist territories, according to the traditionalist view, would have been the main reason for their decision to let North Korea invade the South and create a massive outbreak.
On the other hand, there are a large number of other factors that were, or could have been, decisive reasons for the outbreak in Korea. The revisionist theory speculates that the key factor in the outbreak of a major conflict was the instability and hostility within Korea. Despite how it is viewed today in comparison to North Korea, South Korea (or the Republic of Korea) was not as ‘democratic’ as it truly claimed when created in 1948. Syngman Rhee’s regime was extremely repressive, and frequently imposed policies that were neither fair nor impartial on citizens; crack downs on communist-inspired rebellions were very fierce. In October 1948, 2000 police mutinied at Yeosu because they sympathized with the rebels, who protested against the