Well, this was my question some months ago, when Oakland, California, decided it wasn't going to cooperate with enforcement of federal immigration laws.
The city of Oakland has been a substantial beneficiary of federal dollars; everything from financial aid to its schools to social security payments to grants to its libraries and law-enforcement to food stamps, &c., &c., &c.
It seemed rather peculiar to me, that a place would tell the government, yes, yes, yes, we want your money, but no, no, no, we aren't going to cooperate with your enforcing laws in our place.
It's sort of like the Vermontese separatists, who want that Godforsaken place to be an independent nation, free of the United States.....but who at the same time expect that Patrick "Joe McCarthy" Leahy and Jr. from Vermont could continue representing them in the U.S. Senate.