In 2013, the world was shocked by horrific sarin gas attacks on the opposition-controlled Damascus suburb of Ghouta that killed hundreds of civilians.

　　The government of President Bashar al-Assad denied conducting the attacks, but did accept a Russian-U.S. deal to declare its chemical weapons stockpiles and allow international inspectors to remove and destroy them.

　　UN Seeks Accountability for Syria Gas Attacks

　　But despite their verified destruction, in February, the Organization for the Prohibition of Chemical Weapons (OPCW) said its monitors were highly confident that the toxic chemical chlorine had been used repeatedly and systematically as a weapon.

　　Chlorine has been dropped in barrel bombs from aircraft. The Syrian opposition does not have any planes or helicopters, only the government.  The government has repeatedly denied carrying out such attacks. On Friday, Syria's U.N. envoy repeated that denial in the council and described witness testimony about attacks by government aircraft as “fabrications.”

　　The United States worked for several months on the Security Council resolution seeking accountability for those who commit such attacks.

　　U.S. Ambassador Samantha Power said the new mechanism sends a strong message, “that now finally the international community has the tools to identify you — the perpetrators — and we intend to do so.”

　　The new resolution establishes a joint U.N.-OPCW investigative mechanism to determine who has used chemical weapons in Syria. Until now the organization has been authorized only  to determine that chemicals had been used, but not by whom.

　　The U.N. secretary-general and OPCW director-general now have 20 days to give the Security Council their recommendations for establishing the mechanism. Once the council agrees to those recommendations, the mechanism will become operational for an initial period of one year.

　　Power called the lengthy negotiations “painstaking.” After meetings this week between U.S. Secretary of State John Kerry and Russian Foreign Minister Sergei Lavrov, agreement was finally reached on the text.

　　Russian envoy Vitaly Churkin told reporters that drafting the resolution was challenging because they were putting together an “innovative” mechanism. He said he hopes cooperation could continue on the political track, noting the council is working on a statement of support for U.N. Syria envoy Staffan de Mistura. Churkin said consensus on that would be “another very important step in our working together on difficult matters.”