A federal judge has thrown out a Justice Department lawsuit against a Michigan county after a DOJ attorney admitted in court that no case law supported the government's central argument.

In a decision issued Friday, U.S. District Judge F. Kay Behm, an appointee of President Joe Biden, dismissed all six counts of the DOJ's suit against Washtenaw County, which includes Ann Arbor and the University of Michigan's main campus. The dismissal can be appealed to the U.S. Court of Appeals for the Sixth Circuit. The county had ended its cooperation with federal immigration authorities and restricted Immigration and Customs Enforcement's access to county property and jail cells.

Behm framed the case as the latest in a series of efforts to compel local governments to carry out Washington's agenda under President Donald Trump.

"This is one of a series of lawsuits in which the President of the United States has sought to compel states and localities to do the work and bear the cost of enforcing his preferred immigration agenda," Behm wrote.

The litigation record matches that framing: the Justice Department has filed similar suits against other state and local governments, including Illinois and New York, over policies limiting local assistance to ICE.

The judge was blunt in describing the decision to sue after the county redirected its resources toward local policing.

"Apparently flummoxed by the County's decision to focus its resources on local priorities and public safety, the United States sues to demand Washtenaw County's cooperation, the use of its jail cells, and its resources," she wrote.

The ruling rested on the Tenth Amendment's anti-commandeering doctrine, which bars the federal government from forcing state and local officials to carry out federal policy. The Supreme Court has reaffirmed that principle across three decades, from New York v. United States in 1992 and Printz v. United States in 1997 to Murphy v. NCAA in 2018, which held that Congress may not conscript states into administering federal regulatory programs.

"But neither the federal government nor the President may conscript local officials to enforce their will," Behm wrote.

The most consequential moment came during oral argument. According to a footnote in Behm's opinion, the Trump DOJ's own attorney conceded that a central pillar of his statutory interpretation had never been endorsed by any court.

"At oral argument, Plaintiff's counsel admitted that he was not aware of any case that supports his argument," Behm noted, without naming the DOJ lawyer in question.

Behm accused the Trump administration of attempting to rewrite the rules through the back door and rejected its insistence that it was not asking the county to hold anyone.

"The government attempts to smuggle in two sea changes in immigration law enforcement through this view," Behm wrote. "But as this court has recently reminded a self-represented litigant, 'saying so does not make it so.'"