Would Crime Rates Or Drug Use Be Lowered By The Legalization Of Certain Drugs?

Crime rates would drop simply because of the fact that people won't go to jail for possession or distribution of these drugs. It could have an adverse effect though because if certain drugs were legal more people might be more likely to get addicted to a legalized drug and would have to find ways still to support their habits.

Significantly. And there would also be a huge savings for the government because there'd be less law enforcement needed to fight the "drug war", less spent on prisons and that money could be better spent in other areas of law enforcement to keep citizens safe. It's a win win situation and most studies show this to be true but unfortunately there's big money to be made in the drug war so i think that's one huge reason some drugs are illegal and others are not.