I would not be surprised if the negative social effects of legalizing drugs did not outweigh the present negative social effects of criminalizing them. That’s to a considerable extent because we export a lot of the negative effects to Mexico and elsewhere.
Mexicans like this poor lady die because Americans want to get high.
That wouldn’t happen, but if legalized it is certain that drug usage would increase. We’d see a lot more of the bad effects of the drug itself, and a lot less of the side effects of attempting to outlaw use.
Whether A would be less than B is a good question, and I don’t have the answer.
Calling them "negative social effects" obscures a very important difference: the latter mean real crimes with actual unwilling victims, whereas the former are willingly self-inflicted and for the most part affect the rest of society only to the extent that society has chosen (through its elected representatives) to allow itself to be affected.
if legalized it is certain that drug usage would increase. We’d see a lot more of the bad effects of the drug itself
Where is the evidence that we'd see "a lot" more? Will YOU start using heroin if it's legalized?