Questions are mounting over who represents Washington in Damascus, with claims that the top US diplomat there has an extremist past — bad news for the credibility of US Syria policy.

• The senior US representative in Syria is accused of once belonging to ISIS and publicly defending beheadings.
• Journalist Lindsey Snell, who reported from Syria during and after the war, says this same person once threatened her.
• Syria's current president, Ahmed al-Sharaa, founded the al-Qaeda affiliate that controlled much of the rebel-held north.
• Those groups ran foreigner kidnappings as a business, branding journalists and aid workers as spies and demanding million-dollar ransoms.
• Former enemies are now official partners, raising questions about who the US actually backed in Syria's war.

Outlook: Expect pressure on the State Department to explain the vetting behind its Syria posting as the allegations spread.