The Illegal Immigration Reform and Immigrant Responsibility Act of 1996 requires states and municipalities to cooperate with federal authorities on immigration requests:
A “State, or local government entity or official may not prohibit, or in any way restrict…sending to, or receiving from, the Immigration and Naturalization Service information regarding the citizenship or immigration status, lawful or unlawful, of any individual. (8 USC 1373)
That same law empowers a president to withhold federal financial support from cities and states that thwart the law by ignoring detainer requests. It also includes the failure to honor outstanding deportation orders.
Citing the above statute, the Department of Justice issued a report declaring that the policies and practices of sanctuary jurisdictions violate federal law and can be deprived of federal funds.
Numerous polls show that a majority of Americans are fed up. They endorse a policy of mass deportation for immigrants living in the country illegally, particularly those who have committed crimes and others with existing deportation orders.
https://www.foxnews.com/opinion/prosecute-sanctuary-officials-who-defy-trumps-deportation-orders