The suit asserts that sanctuary laws in Chicago, Cook County and Illinois have obstructed federal efforts to enforce immigration policy.

The U.S. Justice Department sued the state of Illinois and city of Chicago on Thursday, accusing the Democratic strongholds of unlawfully interfering with Republican President Donald Trump's crackdown on illegal immigration and seeking a court order blocking so-called sanctuary laws.

The lawsuit argues the U.S. Constitution’s Supremacy “prohibits Illinois, Chicago, Cook County, and their officials from obstructing the Federal Government’s ability to enforce laws that Congress has enacted or to take actions entrusted to it by the Constitution.”