Some marijuana legalizers push the argument that legalization will generate additional tax revenue. Opinions differ widely, however, on exactly how much revenue.

In mid-February, Colorado Governor John Hickenlooper predicted that the taxes, licenses, and fees on medical-plus-recreational marijuana would generate $134 million for the fiscal year starting in July.

In my 2010 Cato White Paper, I predicted that full legalization (federal and state) would generate roughly $55–60 million per year for Colorado.

Now just released data from Colorado for January, the first month of fully legal marijuana sales, show about $2 million from recreational marijuana and about $3.5 million for medical-plus-recreational marijuana. The latter figure implies annual revenues of about $42 million.

This January figure may turn out to be misleading. On one hand, the industry could grow over time, boosting revenues. On the other hand, initial hoopla over legalization may have inflated January sales. And, longer term, sales in Colorado could decline if other states legalize or medicalize.

If the lower revenue numbers persist, does that weaken the case for legalization?

No: Increased tax revenue was never the main reason for legalization. Instead, the crucial goals of legalization are greater freedom for marijuana users and elimination of prohibition’s unintended consequences (crime, corruption, poor quality control, diminished civil liberties, restrictions on medical uses, and expenditure on enforcement).

Collecting revenue on legalized marijuana is perfectly sensible; it allows lower tax rates on everything else. But this appears to be a small effect, and it is not the main benefit of legalization in any case.