Speaker John Boehner sent a letter to President Barack Obama Wednesday seeking a “clear, unambiguous explanation” of how a strike on Syria fits into U.S. objectives and questioning the president’s legal authority to do so absent Congressional authorization, Roll Call reports. More than 100 lawmakers, including 18 Democrats, have signed a letter that says President Obama would violate the Constitution by striking Syria without first getting authorization from Congress.  According to The Hill, a total of 116 lawmakers had signed the letter as of 6 p.m. Wednesday, highlighting bipartisan interest and growing momentum in ensuring a role for Congress in any decision to use force in Syria. Meanwhile, as the U.S. and its allies move to strike Syria, the Washington Post reports nervous Israelis are rushing for gas masks.