Mr Obama has been roundly criticised by top experts and members of his own administration for instating an approach to the Syrian war – which has seen estimates of more than 400,000 people killed – that is riven with contradictions.

The White House remains notionally committed to removing Mr Assad, whilst at the same time, working in alliance with Russia, Damascus’ top champion.

The new agreement it was setting out with Moscow earlier this month would see US forces join Russia in a bombing campaign against Jabhat al-Nusra, an Islamist group that includes cells who are allied with Al-Qaeda, but whose focus has been combatting the Syrian government.

As America switches its focus to destroying Isil and creating alliances with Moscow, the White House has quietly dropped its rhetoric against the Assad regime.

Critics warn that this approach will only foster anti-American sentiment among Syrians, who feel abandoned by the United States following its failure to take decisive action against Damascus.

A source with access to White House officials said the administration sees the dangers that partnering with Russia could have in terms of worsening the dynamics on the ground, but that the president is trying to cover his bases until he steps down in November.

The source said the White House feels it cannot not be seen to be doing nothing against an Al-Qaeda affiliate at a time of heightened national security in America. Were there to be an attack in the US that was claimed by Al-Qaeda the president’s legacy would be destroyed, they fear.