Per James Fallows at the Atlantic, Obama has a constitutional obligation to fire McCrystal. Article II, Section 2 makes the President Commander in Chief. As such, he must act swiftly to
- stop disrepect for the chain of command.
- protect the security of the US against public discord within that chain of command and public scorn for one’s own current government, and
- protect civilian oversight of the military.
McCrystal has to say bye-bye, but please please please Mr. President, require him to do so.