Don't be so sure about balancing the budget on the back of drug users: http://money.cnn.com/2013/05/10/smallbusiness/marijuana-taxe...
I've always thought that the tax argument was less than stellar. Are we really wanting to convince government that it should legalize drugs because of the money it could make, rather than having a society with more freedom? Is the purpose of a government to make money?
Are there really that many people in the country that are upright about drugs? I've never done a drug in my life but I certainly don't care if others do in a manner similar to alcohol.