"The Chinese historically never supported external intervention and particularly the use of force against a regime," says Bonnie Glaser, senior adviser for Asia at the Center for Strategic and International Studies.
China might also have been burned by the intervention in Libya. Neither Beijing nor Moscow vetoed the U.N. resolution that eventually led to a NATO-led military intervention, which led to the ouster of Moammar Gadhafi. China believed that action went beyond the resolution's mandate.
China will continue to support Assad "until it becomes clear that the wind was blowing the other way," Glasser says."
Who Are Syria's Friends And Why Are They Supporting Assad? : Parallels : NPR