The tensions in the Korean peninsula are like a jar of kimchi that has been fermenting way past its expiration date. It's been six decades since the signing of the Korean War “police action” cease fire. The divisions between the two Koreas have only intensified with time and are far wider than the demilitarized zone that separates the North and South near the 38th parallel. In the immediate aftermath of the Second World War, the Americans and Russians decided that Korea would be divided in half under the control of the two super powers. The Koreans didn't get the memo and weren't consulted on the deal, but have been living with the consequences ever since.
Both the U.S. and Soviet Union orchestrated the establishment of “cooperative” governments in their respective “spheres of influence.” The Russian army is long gone, but our military is still there with around 28,000 troops stationed in South Korea serving as a trip wire to bring us “back to the future” in the Korean War part two.