I've heard lots of arguments pro and con today on the bill introduced in Congress by Barney Frank and Ron Paul to allow the states to legalize marijuana without federal interference, so I thought I'd throw my two cents out there.
I think the best argument for the legalization of marijuana is not the civil liberties one, nor is it the "it's only fair" argument. To me, the best argument is that it takes money out of the hands of the drug cartels and puts it into American coffers.
In the 1920's America experimented with prohibition - the illegalization of alcohol - and all it did was make gangsters richer and make average citizens criminals. It's the same today with marijuana. Back then, once the country wised up and re-legalized alcohol, the gangsters got out of the liquor business and had to find another source of revenue (for most it was drugs.) So (the argument goes) let's legalize marijuana and give today's gangsters one less source of revenue.
It's a powerful argument - one that almost has me convinced!