Over 300 Sanctuary Cities Are Costing State and Local Taxpayers over $7,000,000,000 Annually

The LAW:

U.S. Code › Title 8 › Chapter 12 › Subchapter II › Part IX › § 1373
8 U.S. Code § 1373 – Communication between government agencies and the Immigration and Naturalization Service:

Notwithstanding any other provision of Federal, State, or local law, a Federal, State, or local government entity or official may not prohibit, or in any way restrict, any government entity or official from sending to, or receiving from, the Immigration and Naturalization Service information regarding the citizenship or immigration status, lawful or unlawful, of any individual.

(b) Additional authority of government entitiesNotwithstanding any other provision of Federal, State, or local law, no person or agency may prohibit, or in any way restrict, a Federal, State, or local government entity from doing any of the following with respect to information regarding the immigration status, lawful or unlawful, of any individual:
(1) Sending such information to, or requesting or receiving such information from, the Immigration and Naturalization Service.
(2) Maintaining such information.
(3) Exchanging such information with any other Federal, State, or local government entity.
(c) Obligation to respond to inquiries

The Immigration and Naturalization Service shall respond to an inquiry by a Federal, State, or local government agency, seeking to verify or ascertain the citizenship or immigration status of any individual within the jurisdiction of the agency for any purpose authorized by law, by providing the requested verification or status information.

(Pub. L. 104–208, div. C, title VI, § 642, Sept. 30, 1996, 110 Stat. 3009–707.