Allen, now president of the Brookings Institution, also focused his criticism on the president’s threat on Monday to deploy the US military against protesters, and his use of force against a peaceful demonstration outside the White House so that he could be photographed holding a Bible in front of a church.

A battalion from the elite 82nd Airborne Division, and two brigades of military police, were flown from their bases in North Carolina and New York to the Washington area at the beginning of the week, apparently to be on standby if the Insurrection Act was invoked.

A White House spokesman, Hogan Gidley, said on Thursday “all options are on the table” in terms of the use of active duty troops.

Kayla Williams, who served as an intelligence officer in the 101st Airborne Division, said the flurry of public and private statements “reveals deep unease, even among senior levels, and a real lack of cohesion among the senior levels of our government at this point”.

“Among the rank and file there also seems to be a great deal of discomfort at the prospect of having to intervene in civil unrest,” Williams, now a senior fellow at the Centre for a New American Security, said.

James Dubik, a retired lieutenant general and a senior fellow at the Institute for the Study of War, said service members swear an oath to the constitution, and are at the same time obligated to follow the legal commands of the president