No. of Recommendations: 12
It's called the Supremacy Clause, part of the U.S. Constitution. Federal law preempts state and local law.
Yes, I'm very familiar with it. I'm a zoning and land use lawyer, and from time to time I've had to deal with Supremacy clause issues as they've come up pertaining to local regulation of federal facilities.
The Supremacy Clause is not a blank check exemption. Federal officials are required to comply with all state and local laws unless there is a conflict with a federal law or the exercise of federal function. Moreover, federal regulation is constrained by the anti-commandeering doctrine under the Tenth Amendment - basically, the 10th ensures that the federal government can't require the States (or their instrumentalities) to use their resources or personnel to implement or enforce federal programs or regulations.
Which is why your statement:
Mamdani, as Mayor of NYC, or as a candidate, has no greater power than you do to "stop ICE."
....is incorrect. If Mamdani is elected Mayor, he will have the legal authority to exercise a number of governmental powers, which powers ultimately derive from the State of New York, which are protected by the 10th Amendment and which will bind even federal officials unless there is an actual conflict with a federal law. That's far more power than I have.
So if, for example, NYC were to adopt the sorts of laws that California has adopted to try to cabin how ICE operates at the intersection of state and local law power, those would probably be fine under the Supremacy Clause. The anti-mask ones will probably be the subject of more serious litigation, and the Federal government might prevail. But most other "sanctuary city" type laws have managed to find legality under anti-commandeering or by avoiding direct conflict with federal law.
