It appears to be the first Justice Department lawsuit against local officials for allegedly interfering with the Trump administration’s immigration crackdown.

The lawsuit argues that the U.S. Constitution’s Supremacy Clause “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.”

Illinois joined the legal battle against the Trump administration Thursday as a federal judge temporarily blocked an order to end birthright citizenship.