Their justification currently contains two main reasons for a missile attack against Syria. First, Syria used poison gas to kill 1,400 people, including 400 children. Subsequently, the Syrian government needs to be punished for this bad act so it won't do it again. Secondly, the "word" of the U.S. government is on the line because of President Barack Obama's "... crossing a red line" statement. Therefore, if the words of the U.S. government are to have any meaning, an act of war must be committed to maintain it's creditability.