1) Oil prices and economic inefficiency.
Yamani, declared that Saudi Arabia was quitting the agreement on oil production restraint, and started to boost its share in the oil market. After this, Saudi Arabia increased oil production by 5.5 fold, and oil prices dropped by 6.1 fold,
2) ethnic tensions
3) Gorbachev’s reforms
I think morally wrong because it started the nuclear age. Even if the Chinese did wrong to us, they didn’t deserve that. Especially innocent people.