The Trump administration is imploring the Supreme Court to show “extraordinary deference” to the president as commander-in-chief and affirm the lawfulness of his National Guard deployment to Illinois, arguing in a new court filing that federal agents conducting immigration enforcement are unable to do the work on their own. 

A letter from Solicitor General John Sauer to the justices on Monday addresses their request that both parties in the case explain the meaning of a key part of federal law governing when a president can send in troops. 

Section 12406 of the federal code says a president may call up the National Guard when he is “unable with the regular forces to execute the laws of the United States.”

The Supreme Court said it was interested in finding out what exactly the term “regular forces” means. 

Sauer argued in the letter that it does not refer to the standing military — which Trump has not attempted to deploy in Illinois — but instead refers to the “civilian forces that regularly ‘execute the laws’ at issue but are ‘unable’ to do so in present circumstances,” or the ICE and DHS agents on the ground. 

“Given the nature of the problem in Illinois, it was a reasonable exercise of the President’s discretion to deploy National Guardsmen, who are civilians temporarily called up to serve with deep experience in deescalating domestic disturbances among their fellow citizens, rather than the standing military, whose primary function is to win wars by deploying lethal force against foreign enemies,” Sauer told the Supreme Court. 

“It would turn Section 12406(3) on its head to insist that the President must nevertheless instead use the standing military to protect DHS agents while they execute federal immigration laws,” he wrote. 

Illinois and the city of Chicago, which are challenging the legality of Trump’s deployment, have accused the administration of contorting the law. They are expected to file a response letter with the Supreme Court by next week.

The Trump administration last month filed an emergency stay request with the Supreme Court to undo a lower court order blocking the deployment of the National Guard in Illinois.

Lower federal courts have kept the president’s troop deployment on hold in Illinois, finding his stated justification does not meet the criteria under the law.  

Trump has said Guard troops are needed for crime prevention in Chicago, which he has described as a “war zone.” 

In addition, the Trump administration has said troops are needed to protect federal immigration facilities, which have been the site of clashes between protesters and federal immigration agents as the administration carries out its stepped-up immigration enforcement.