Obama loves states’ rights. Except for when he doesn’t. But when it comes to pot, Obama wants Congress to remove a rider overturning the effective legalization of pot in DC.

Press secretary Josh Earnest said that the president generally backed DC statehood and that the administration did “not believe Congress should spend a lot of time interfering with the citizens of District of Columbia.” … The president said [in reference to Colorado’s referendum] that it was “important for it to go forward because it’s important for society not to have a situation in which a large portion of people have at one time or another broken the law and only a select few get punished.”

Just why Obama likes states’ sovereignty on pot but not on same-sex marriage is a bit of a mystery. But his comments on Colorado’s legalization might shed some light on his reasoning. Perhaps he thinks that the enforcement of marijuana laws unfairly targets African-Americans. That does seem to be the upshot of the statement that a “large portion of people” are breaking the law and only a “select few” are being punished for it.

That might be a bit of an exaggeration, but not by much. According to statistics compiled by the ACLU, black people are arrested for marijuana usage at more than twice the rate of white people in spite of data indicating that marijuana usage is fairly evenly distributed across the races.

Of interest is the fact that marijuana legalization seems to be occurring only for majority white populations:

But it’s hard to make the case that decriminalization made enforcement more equitable. Indeed, as Stanford med school Professor Keith Humphreys notes, the states that have legalized or decriminalized marijuana to date all have smaller-than-average black populations. That suggests that whatever benefits casual marijuana users have received from those policies have mainly accrued to white smokers.

In other words, Obama supports DC legalization more as a matter of social justice than of states’ rights. As you might expect.