"The Department of Justice today filed a statement of interest in an Illinois federal court in support of a lawsuit filed by Illinois state representative Darren Bailey challenging certain actions of Governor J.B. Pritzker..."

"... in response to the COVID-19 pandemic. The Statement of Interest is part of Attorney General William P. Barr’s April 27, 2020 initiative directing Assistant Attorney General Eric Dreiband for the Civil Rights Division, and the U.S. Attorney for the Eastern District of Michigan, Matthew Schneider, to review state and local policies to ensure that civil liberties are protected during the COVID-19 pandemic.... According to the lawsuit, the Governor’s actions are not authorized by state law, as they extend beyond the 30-day time period imposed by the Illinois legislature for the Governor’s exercise of emergency powers granted under the Act.... In its statement of interest, the United States explains that this dispute belongs in Illinois state court... Although the complaint does not raise any federal constitutional claims, the statement explains... states must comply with their own laws in making these sensitive policy choices in a manner responsive to the people and, in doing so, both respect and serve the goals of our broader federal structure, including the guarantee of due process in the U.S. Constitution."

A press release from the U.S. Department of Justice.

So... it's an Illinois state law question that belongs in Illinois state court, which is where it is but was and the Department of Justice would like to say that states should follow their own laws and should make policy choices carefully because it's at least conceivable that there could be a federal law issue in there somewhere. Might violate due process in some way, might not "serve the goals of our broader federal structure" — whatever that means.

If you're trying to remember the recent post here about Darren Bailey — it's here, 2 days ago. He was the one Illinois legislator who refused to wear a mask in the legislative chamber and got kicked out.

CORRECTION: As the heading of this post says, the case is in an "an Illinois federal court," so I was wrong to write "it's an Illinois state law question that belongs in Illinois state court, which is where it is."

ADDED: Here's a Chicago Sun Times article explaining that Pritzer filed on Thursday to remove the case to federal court, which he has the right to do under federal law if Bailey has stated a federal cause of action: "The governor made the move on the grounds that Bailey alleged a violation of his federal constitutional rights. [Bailey's lawyer] denied that Bailey had raised such a claim." Another Bailey lawyer says the effort to remove to federal court is “perhaps the most outrageous invocation of federal jurisdiction imaginable" and "an egregious attempt to neuter a state court."

So the DOJ's statement isn't about the hint of federal law in the background. It's about the federalism value letting state courts determine the meaning and application of state law. This isn't just a matter of  letting states function separately in our federal system. It's a matter of getting an authoritative interpretation of state law.