German news magazine Der Spiegel recently interviewed Harvard's Professor Jeffrey Miron on legalization.
In the piece, Miron estimated that the US "could save $85 billion to $90 billion per year" if it legalized drugs. Miron also said:
"If you believe in anything that the Americans claim to believe in -- freedom, individuality, personal responsibility -- you have to legalize drugs. The maxim should be that you're allowed to do it if you're not harming anyone else. There is an assumption that you're harming someone when you take drugs, but the scientific data doesn't support this hypothesis."