Originally Posted by Platapus

Under the War Powers Act of 1973, the POTUS can only introduce US Armed Forces into hostilities under one of only three conditions

1. A declaration of war by Congress
2. Specific statutory authorization (this is what President Obama is asking for)
3. "a national emergency created by attack upon the United States, its territories, or possessions, or its armed forces." That is a direct quote from the War Powers Act of 1973.

It would be difficult to consider what is happening in Syria as applying to item 3.