Well, 'messy' wouldn't even BEGIN to cover it

2. He means that even if Congress votes against authorizing the Syria war, he can still order the strikes because he didn't have to ask Congress in the first place.

If Congress votes to withhold authority for the strikes and Obama orders them anyway, then beyond question we will have reached one of the most serious Constitutional crises of our history.
followed by
But there is another component of what such a position might mean. Suppose my hypothetical news story comes true and Obama order the attacks even though Congress specifically withholds authority.

I would maintain that our flag-rank military officers are duty bound to disobey those orders.
If correct(and I'd think he is), then any officer who obeyed the orders would be looking at court martial. 
Which could make it even worse, if the Joint Chiefs announce something like "We had orders from the President, so we can't second-guess those just because of Congress."  The ramifications of that...
"Our oath to the Constitution is trumped by orders from the President."
"Are you out of your fucking mind?" from lots of officers who actually believe in that oath.  It could- likely would- destroy our military, at the least it would trash trust and honor.

And Congress would really have only two options:
Roll over and announce "We're not going to take any action against this President, no matter what he does."  At which point they've demonstrated that they need to be removed from office as soon as possible for breaking THEIR oath, betraying a huge trust placed in them.
Or
File the charges.  Impeachment.

The Evil Party leadership would rather set off a nuke in Yellowstone to fire off an eruption than try to rein in Obama.  And most of the Stupid Party leadership doesn't have the balls or integrity to do it on their own.

The term 'clusterfuck of Biblical proportions' comes to mind.