Which presidential candidate will address the nullification of federal law by major cities across the country declaring sanctuary for illegal aliens?

After ignoring a Freedom of Information Act (FOIA) request – but before the subsequent lawsuit went to court - Judicial Watch received from Washington, D.C.'s Metropolitan Police Department (MPD) a memo from former Police Chief Charles H. Ramsey that states:

"MPD [Metropolitan Police Department] officers are strictly prohibited from making inquiries into citizenship or residency status for the purpose of determining whether an individual has violated the civil immigration laws or for the purpose of enforcing those laws…the MPD is not in the business of inquiring about the residency status of the people we serve and is not in the business of enforcing civil immigration laws."

Et tu DC?

Section 642 of the Illegal Immigration Reform and Immigrant Responsibility Act of 1996 (8 U.S.C. § 1373) in effect prohibits any interference in the free exchange of immigration-related information between state or local law enforcement and federal immigration authorities.

Houston, LA, Chicago, DC, etc. have some explaining to do, but who of our would-be presidential candidates is brave enough to take on the question?  Will Matthews be brave enough to ask it?