One of the reasons why the 1962 Cuban Missile Crisis did not escalate into a war was due to the diplomacy of Adlai Stevenson in the UN. Are there other instances where the defusing of a serious crisis could be attributed to UN diplomacy?
Edit: I'm looking for instances where the defusing of highly tense brink-of-war situations were attributed to actions either directly or indirectly involving the UN.
What comes to my mind is the Suez Crisis of 1956. After a series of engagements between Israeli and Egyptian forces, mostly on the Sinai Peninsula, a UN force called the United Nations Emergency Force was sent in to stop further hostilities.
This was during the cold war, when Israel was backed by the US, of course, while Egypt had the support of the Soviet Union. Relations between those two superpowers were not too good then. Therefore, I would say that there were parties on the brink of war (while others, Israel and Egypt, already actuall were at war) and count this an example of the UN "defusing", as you put it, a highly tense situation.
The United Nations has helped in various situations, but there aren't many where they have been the major presence in solving conflict. However, they have done good, such as by using pressure to encourage North/South Sudan talks.
