Way too late for all that, even if we outlawed it 20 years ago, somewhere, someone already has this. Its in our nature, and to fight it is cognitive dissonance. The "arms race" will built us up, and tear us down till the end of time.

Musk, Hawking, Wozniak: Ban AI warfare, autonomous weapons

http://www.extremetech.com/extreme/210983-musk-hawking-woz-ban-ai-warfare-autonomous-weapons