Timeline of the Syria chemical weapons saga
http://thinkprogress.org/security/2013/08/28/2539341/syria-chemical-weapons-saga/
Aug. 20, 2012: President Obama during a speech on the threat of weapons of mass-destruction warns against chemical weapons use in Syria, for the first time setting the U.S. red-line against such a move. That would change my calculus, he said. That would change my equation. The warning serves as the first U.S. threat of intervention in the conflict through military means, at a time when it is becoming more obvious that the civil war would be lengthy.
Dec. 3, 2012: Obama repeats his warning to Assad in a speech at the National Defense University, saying The use of chemical weapons is and would be totally unacceptable. And if you make the tragic mistake of using these weapons, there will be consequences and you will be held accountable.
Mar. 19, 2013: Syria claims that rebel fighters used chemical weapons against government forces during fighting outside of Aleppo, killing 26 people including government soldiers. To add credibility to their claim, Damascus writes to United Nations Secretary-General Ban Ki-Moon to send in a team of investigators to confirm. The Syrian oppositions denies the regimes claims, saying the weapons were actually unleashed against them, echoing the call for an investigation.
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