Stephen Moore, a conservative economist who has advised the president, said: "Candidates are always bombastic on the campaign trail, and Trump especially, but there is some growing into the office and dealing with the real effects of some of the policies.

"But if he starts just abandoning his promises, then I think it's going to exact a political toll."

For some of Mr Trump's supporters the recent policy reversals have been too much.

Ann Coulter, the prominent conservative commentator and fervent backer of Mr Trump, said: "I've had a knot in my stomach since he's been filling up his administration with these warmongers and Wall Street types. If we wanted meddling in the Middle East, there were other candidates to vote for.

"Trump was very clear and he was very right, and that's why Trumpism will live on whether or not he believes in it anymore."

Intervening in Syria

In his Inauguration speech President Trump said "From this day forward it’s going to be only America first."

The phrase harked back to the "America First' movement that was opposed to US intervention in the Second World War and appealed to Americans weary of the long and costly interventions in Iraq and Afghanistan.

Mr Trump himself has always maintained he is not an isolationist, but his rhetoric on the campaign trail was clearly opposed to getting the US involved in another "disaster" like Iraq.