Two leading Republican lawmakers, Sens. John McCain and Lindsey Graham, said Tuesday that reports of chemical weapons use in Syria, if true, mean the president's threshold for involvement in the country's civil war has been met. They said that if the reports of a Scud B hitting Aleppo with a poison warhead are substantiated, “The President’s red line has been crossed, and we would urge him to take immediate action to impose the consequences he has promised."