Cuba Arms Treaty
The Cuba Arms Treaty was a United Nations agreement signed by 130 nations in 1963, following the standoff between US and Soviet forces during the Cuban Missile Crisis.
Exacerbated by the disastrous 'Bay of Pigs' invasion in 1961, Soviet and US tensions were at an all-time high. DEO operatives from Stormwatch were present in Istanbul, on the Russian border; Russian elite troops from the Winter Guard were congregating in Cuba. Both were there to protect missile installations aimed at the heart of the other nation, with orders in hand to cross the border unless given specific orders otherwise by the White House.
Disaster was averted at the 11th hour, minutes before John F Kennedy's plan to invade Cuba and Russia was to begin. Wesley Dodds burst into the White House situation room with comprehensive evidence that the entire affair was being orchestrated by members of HYDRA, at that time considered part of the Nazi remnant forces that had not surrendered. A hotline to the Soviets confirmed this information and all sides called off their troops.
The Cuba Treaty limit the use of metahumans in armed conflicts and create metahumans as a protected class of citizen. They also limit production and use of autonomous drones (and in 2018, proto-sapient AIs) for military or police purposes. Countries signatory to the Treaty may not deport their metahuman residents and theoretically cannot force relocation (though America and others maintain Mutant Town and other districts that are a product of forced resettlement policies).
China, North Korea, Myanmar, Saudi Arabia, Pakistan, Iran, Chad, Congo, and San Salvador all declined to sign the treaty.