Israel spies & Syrian operatives contaminating soil samples, but US 'amends red line'

"... None of the assertions — by Israel, Britain or France — have included physical proof. Experts say the most definitive way to prove the use of chemical weapons is to promptly collect soil samples at the site and examine suspected victims...A senior Defense Department official noted that “the use of chemical weapons in an environment like Syria is very difficult to confirm.” He added: “Given the stakes involved, low-confidence assessments by foreign governments cannot be the basis for U.S. action. The president has clearly stated that the use of chemical weapons would be a game changer. Thus, we must be absolutely confident of use before determining how to respond.”...
Mr. Obama’s aides have since amended his statement, saying that he was referring to major use of chemical weapons — akin to what Saddam Husseinemployed against the Kurds two decades ago — or the transfer of weapons to terrorist groups. Mr. Hagel’s spokesman, George Little, said in Amman, Jordan, where Mr. Hagel arrived on Tuesday, that the president’s warnings remained in place...."