North and South Agreement
The Korean War ended in an armistice, neither sides were able to claim outright victory and not any successes came from it. Korea suffered many consequences that to this day they still face and ultimately the war should be seen as a failure. The truce is still all the technically prevents North Korea and the US/South Korea from resuming the war, as no peace treaty has ever been signed. Both sides regularly accuse the other of violating the agreement, but the accusations have become more frequent as tensions rise over north Korea's nuclear programs. (Encyclopedia Britannica)
The main reason why Korea could not unite was because the Demilitarized Zone, along with the US sanctions that prevented much import and export for Korea, and as well as the two super powers who really just used Korea as a battlefield. Also the two sections could not unite because of the appointment of power between the North and South Koreans. To this day, both Koreas are still divided by the Korean DMZ that has cause much tension between the two sides. (Korean War Not Forgotten)
