Homeland security secretary Kirstjen Nielsen told the Senate Judiciary Committee that her agency has asked the Justice Department to look into pursuing criminal charges against the leaders of sanctuary cities.

ICE director Tom Homan said previously that sanctuary city policies put his officers at risk because they have to make arrests out in the community rather than local jails, where illegals who have committed additional crimes are held awaiting trial.  Ordinarily, ICE requests that an immigration "hold" be placed on illegals charged with another crime, giving the agency time to pick them up.  But sanctuary cities refuse to cooperate in enforcing the hold, releasing the illegal when he posts bail.

Washington Times:

Homeland [s]ecurity [s]ecretary Kirstjen Nielsen confirmed Tuesday that her department has asked federal prosecutors to see if they can lodge criminal charges against sanctuary cities that refuse to cooperate with federal deportation efforts.

"The Department of Justice is reviewing what avenues may be available," Ms. Nielsen told the Senate Judiciary Committee.

Her confirmation came after California's new sanctuary law went into effect Jan. 1, severely restricting cooperation the state or any of its localities could offer.

U.S. Immigration and Customs Enforcement [d]irector Tom Homan says those policies put his officers and local communities at more risk because they have to arrest illegal immigrants out in the community.

Mr. Homan told The Washington Times last July that he wanted to see local officials charged as complicit in human[-]smuggling if they shielded illegal immigrants through sanctuary policies.

The Supreme Court has ruled several times that state and local law enforcement do not have to cooperate in enforcing federal immigration law.  That's one of the reasons the president has asked for 10,000 more ICE agents.  The additional personnel will not only patrol the border, but be assigned to cities so they can pick up illegals in local custody if they can identify them as such.

But the legal argument being made by DHS is that by allowing illegals to disappear even if they're charged with an additional criminal act, local officials are facilitating human-smugglinjg.  It's a novel approach, and the circumstances call for it.  By refusing to enforce federal immigration law, state and local governments are practicing a form of nullification not seen since before the Civil War. 

We are not likely to see local officials doing a perp walk from city hall to the jail.  In fact, charging politicians with human-smuggling may not be possible under the law.  But it certainly puts local leaders on notice that the Trump administration is seriously looking at enforcing immigration law and that sanctuary city policies will be fought at the federal level.