The Supreme Court has ruled that the executive branch can't withhold funds unless that penalty is part of the law granting those funds so that the local government can be aware of the penalties at the time that it accepts for those funds. Retroactive rules or penalties are unconstitutional. Further, any such penalties have to be related to the subjects of the grant; highway funds, for example, can't be withhold from sanctuary cities, but they could be withheld from states that don't comply with the National Minimum Drinking Age Act because that act relates to highway safety. Withholding grants to cities or states that decline to enforce all Federal laws would be unconstitutional.

In the Printz v. United States decision (written by Scalia), the Supreme Court ruled that states cannot be conscripted to carry out federal law thus, striking a provision of the Brady Handgun Violence Prevention Act that would have commandeered local sheriffs by requiring them to perform background checks.