Explain how and why Both the USSR and the USA Got Involved in the Korean War

There were many reasons as to why both the USSR and the USA entered the Korean War, however the underlying reason that the Korean War erupted was because it was merely another episode in the ongoing Cold War between these two super-powers. On the surface, the Korean War seemed to be a war between South Korea and North Korea, but in actuality the superpowers were using it as a front to combat each other without actually going into a 'hot war' which - as both had the atomic bomb - would have been a scenario of mutually assured destruction.
<Tab/>The USA went to war in Korea for three main reasons. The first reason was the 'Domino theory'. Salami tactics in Eastern Europe was not the only place where Communists were coming to power. …