Homan is getting people used to the idea that you are in violation of the US Code when you do your "sanctuary" thing. Pretty soon I am positive there are going to be arrests of sanctuary politicians:
8 U.S. Code § 1324 [https://www.law.cornell.edu/uscode/text/8/1324]

Some examples:

(ii) knowing or in reckless disregard of the fact that an alien has come to, entered, or remains in the United States in violation of law

(iii) knowing or in reckless disregard of the fact that an alien has come to, entered, or remains in the United States in violation of law, conceals, harbors, or shields from detection, or attempts to conceal, harbor, or shield from detection, such alien in any place, including any building or any means of transportation