The troops are ready. A US defense official has confirmed that soldiers from the 11th Airborne Division in Fort Wainwright, Alaska, are on standby for a controversial domestic deployment to Minneapolis.

The unit, trained for arctic warfare, finds itself in the strange position of preparing to police American streets. The order has not yet been given, but the preparations are real. It is a moment of high tension, with the military caught between the Commander-in-Chief’s orders and the constitutional norms of Posse Comitatus.