But getting rid of Assad is good all by itself, isn't it?
Oh, of course, just like getting rid of Saddam Hussein was good all by itself. Have you no memory?
Unfortunately, we have been cursed with leadership that chooses to ignore the reality that nothing exists "all by itself." Everything is interconnected, which should be obvious to anyone. But Obama/Kerry don't seem to get it any better than Bush/Cheney did. Their common assumption, that they can control reality and determine outcomes, is a hallmark of hubris (also madness, also bloodthirsty recklessness).
For all the mindless destruction the Iraq war has visited on everyone involved (except the insulated commanders), the indefensible result today is an Iraq that has suffered and continues to suffer far more than it would have had Saddam remained in power. War crimes tend to turn out badly.
So we should leave Assad in power?
The first problem with that question is the assumption that it's up to "us," whoever "us" is. Unquestionably "we" can intervene in any horrific way we choose, and no one can stop us. But that's where our control of events ends, and the benefits of any intervention are hard to identify -- most likely because they are nil.
Of course an attack might briefly satisfy the mindless
impulse to "do something," even if all we accomplished was showing that we were
tough, by teaching Syrians they better not kill Syrians unless they want us to
come in and kill more Syrians.
But chemical weapons are evil, aren't they?
That's really a religious question. But eve if they ARE evil, so what? Foreign policy doesn't involve itself with questions of good and evil.