Newsman Tony Cheng of CGTN, the Chinese English-language TV newschannel has just watched American-supported fighters, led by units of the Kurdish YPG, expel the Islamic State from its Syrian capital Raqqa. He also covered the re-taking of the Iraqi city of Mosul from ISIS. Again Kurds helped win the battle there. But now Iraqi government forces, and Iran-trained militia units are expelling Kurds from the oil-0rich areas around Kirkuk. Will the US defend its once-valued Kurdish allies?