After the end of the Second World War Korea came to be occupied by the US and the Soviet armies along the 38th parallel, US occupying the southern part and the Soviet Union the northern of the line.
In 1949 both the USSR and USA withdrew their forces and thereby gave the Korean people an opportunity to be unite-. Immediately after that war broke out between the two Koreas.
No solution was also possible at the Geneva Conference. The UN also could not do much except reaffirmation of objective of peaceful unification of Korea.
Thus partition of Korea has become a permanent feature at least till now. The great question is under whose leadership, North Korea jot South Korea, would Korea be united?