Same-sex marriage and marijuana legalization won a series of referenda on Tuesday, and good partisans of Federalism should, presumably, cheer. Where does the Constitution say that the Federal Government should have any opinion about personal status law? Where does the Constitution say that the Federal Government should have any opinion about control of mind-altering substances?

Except . . . it’s very hard for me to see how the Federal Government can avoid getting involved.

Federal law contains a variety of preferences for people in a state of matrimony. Refusing to recognize a duly solemnized and legal marriage in Maine or Washington is plainly to have an opinion about personal status – and one that conflicts with the states in question. Recognizing such marriages means giving them national legitimacy – again, that’s the Federal Government offering an opinion.

Advocates for marijuana legalization are fretting now about the DEA disregarding the opinion of the voters in Colorado and Washington – with good reason given the behavior of the Obama DEA in response to much more limited medical marijuana laws in states like California. But the alternative would be something akin to national decriminalization. There’s no customs post in Nebraska to inspect the luggage of visitors to Colorado, after all.

I happen to support national recognition of same-sex marriages, because I think the states should be allowed to innovate in this manner, and the Federal Government should not register a contrary opinion. (For that matter, I also favored the same-sex marriage law in my state, New York.) But I’m not deluded that this formal neutrality isn’t a substantive endorsement. I also happen to support marijuana decriminalization. But, again, I’m not deluded into thinking that legalization in one state won’t make it difficult to impossible to enforce prohibition in a neighboring state. In such a way, a handful of states, if their sovereignty is taken seriously, can change national policy.

Tricky thing, this Federal system of ours.