Urges the United States to work with the United Nations (U.N.) and the international community to exhaust all diplomatic and non-military options to facilitate a negotiated settlement in Syria and hold the Assad regime and all responsible parties accountable for human rights violations, including the use of chemical weapons, through efforts such as: (1) requiring Syria to allow unfettered access to humanitarian organizations; (2) engaging in diplomacy to advance a negotiated settlement; (3) strengthening multilateral sanctions against the assets of President Bashar al-Assad and others who may be involved in crimes under international law; (4) investigating and prosecuting crimes against humanity and other crimes under international law, including referring the situation in Syria to the International Criminal Court; (5) working with member states of the Chemical Weapons Convention to prevent the deployment and use of weapons of mass destruction, including urging Syria to become a Convention signatory, and formulating a plan to place Syria's chemical weapons stockpile under international control; (6) working with the international community to establish a Syrian war crimes tribunal; and (7) enabling U.S. courts to investigate and prosecute crimes against humanity and other crimes under international law committed in Syria.