Ruthlessly efficient AI is the next "big stick". Nuclear weapons brought us relatively close to world peace (after burning up hundreds of thousands of people

Ruthlessly efficient AI is the next "big stick". Nuclear weapons brought us relatively close to world peace (after burning up hundreds of thousands of people and scaring the whole world shitless) maybe ruthless AI can do the same. I'm not particularly eager to see what an AI arms race and cold war looks like though. Things are decent enough right now, it could be a lot worse; do the upsides of creating ruthless AI justify the risks? Is it an eventuality anyway? At this stage could we conceivably prevent it?