The United States’ attempt to deter chemical weapons use by the Syrian government failed largely due to the former's lack of credibility. Having seen its implicit deterrent threats ignored in spring and summer, 2013, the United States scrambled to restore them by threatening to use force explicitly, only to find that its credibility was exhausted. Syria's subsequent pledge to give up its chemical weapons, popularly explained as a response to renewed U.S. threats, likely reflected a strategic environment changed more by developments in Syria than any application of U.S. deterrent strategy.