There are currently cities and other localities that openly disregard federal law. An example is a sanctuary city that openly defies federal attempts to enforce immigration law.
The elected officials of these localities are in open rebellion and defiance of the US Government and the rule of law. Localities shouldn't be able to pick and choose which laws they will obey/support and which laws they will ignore/contravene. These are the laws that bind the Union. It's fine to work through legal/political channels to change a law that isn't liked - but not to openly defy the law and operate in support of illegal activity.
These scofflaws shouldn't benefit at the expense of other cities that follow and support the law. Taxpayer money to these cities should be cut until compliant.