Where does the Constitution say that the President needs approval?

The Constitution empowers the President as Commander in Chief of the armed forces. The executive branch also places foreign policy under the control of the executive branch. If the President thinks that the country should go to war, then yes, the Congress is the branch that declares war, but to further legitimate foreign policy aims, the President can use the armed forces short of declaring war, and in this case, it is in the national interest to discourage the use and spread of chemical weapons in the middle east.

To the everlasting glory of the infantry...

Owain ab Arawn
KGB Supreme Knight
King's High Council