Former Secretary of State John Kerry said former President Barack Obama should have followed through on his infamous "red line" warning to Syria, and the United States "paid a price" as a result of Obama's inaction. Obama vowed in 2012 that if Syrian President Bashar al-Assad's regime used chemical weapons on civilians, it would be a "game changer" for U.S. military involvement in Syria. But Obama failed to enforce the promise a year later when hundreds of Syrians were killed in a sarin gas attack, and he instead brokered a multi-nation deal in which Assad pledged to remove his chemical...