i'm almost positive that weed is illegal in us because the government couldn't effectively tax it, due to the high number of peopel who would grow it, instead of buying the governments product, plus what was mentioned, lots of peopel would turn to it for: insomnia, nasuea, headaches, migrianes, depression (yes it's an anti depressant or was atleast reconized as so like 4k years ago by the chinese) high anxiety among maaaaaaaany others. it would probably take over half the medication we take now, and instead of taking 10 diffrent pills for 10 diffrent symptoms we'd only have to use mary-jane for all of them.