Get a formal declaration of war from Congress before we bomb. Otherwise it is like the Japanese bombing of Pearl Harbor. The last President with the leadership to ask Congress to declare war was Roosevelt. It was also the last war that united the nation. It was also the last war we won. It’s what Presidents should do.
If I were POTUS, I would have drawn a red line for WMD use, but with a small qualification: Any nation using WMD’s on non-Muslim countries will incur an immediate military response.