For those who are still debating if President Obama has the authority to decide any attack on Syria, on his own, please listen carefully the speech given by President Obama ( the Chief of US Military at present) on Syria. For your convenience, 
1:45 - I have decided...
2:43 - I am prepared to give that order...
4:40 - I believe I have the authority...

Video Source: Youtube
- Jangali Maanab