On Monday afternoon, the Trump administration and lawyers for the state of Illinois and the city of Chicago filed additional briefs in response to a Supreme Court order for them to discuss whether, for purposes of the federal law on which President Donald Trump relied to call up the National Guard – which allows him to do so when (among other things) he cannot “with the regular forces … execute the laws of the United States” – “the term ‘regular forces’ refers to the regular forces of the United States military, and, if so, how that interpretation affects the operation” of the law.

The Trump administration told the Supreme Court that the law at issue refers to civilian law-enforcement officers, rather than the U.S. military. And although “the standing military was undoubtedly an available option to quash the violent resistance to federal immigration enforcement,” U.S. Solicitor General D. John Sauer argued, courts should at the very least give “extraordinary deference” to the president’s determination to send the National Guard to Chicago.

Lawyers for the state of Illinois and the city of Chicago countered that the phrase “regular forces” “refers to the full-time, professional military.” And they urged the justices to leave in place an order by a federal judge that bars the president from deploying the National Guard to Chicago, telling the court that the Trump administration had not tried to show, and cannot show, that he could not execute federal law in Chicago with the U.S. military and therefore cannot send the National Guard instead.