The most likely reason for war would be to prevent the other country from achieving world domination by means other than war. John von Neumann (who knew a thing

The most likely reason for war would be to prevent the other country from achieving world domination by means other than war. John von Neumann (who knew a thing or two about game theory) recommended to attack the Soviet Union to prevent it from becoming a nuclear superpower. There is little doubt it would have worked. The powers between the US and China are more balanced now, but the stakes are also higher. A superintelligent weapon would be more powerful than a large amount of nuclear warheads.