Currently the local, state and federal government spend $50 billion a year enforcing, prosecuting and incarcerating marijuana users.
Legalizing it saves the $50 bil, plus, the tax on legally sold Pot would generate $150 billion or a net change of $200 billion in the Government coffers.
Now the real benefit is jobs; planting, cultivating and harvesting would create 250,000 jobs. Distribution and sales would add another 300,000 jobs.
Administrating the sales and staffing the taxing authority would create another 100,000 jobs.
All together it would create 1o,ooo new small businesses with less harm then that of the alcohol business that exists today.
The gateway drug story goes away by tightening up laws for possession of the other drugs with mandatory sentences of 10 years.
It would free up about 100,000 prison and jail cells, use those cells for the other drug users.