How do we legalize Marijuana?

I think it’s largely a matter of ignorance. But maybe we should break it down to everyone that demonizes drugs in a very simple, mathematical, way:
A lot of tax payer money is going to catch criminals, whose only crime is equivalent to smoking a cigarette.
A lot of taxable income is being lost to the underground economy because marijuana is illegal.

Now while I think this should expanded to all drugs, including Crack, I must make some realistic concessions. But all this seems to culminate in a reduced cost, and increased income (both at the same time, more at