Exactly, at least regarding Russia, Syria and Iran.
Syria, Hizbollah, Iran, HAMAS do nothing is response?
I'm not saying that at all. There are plenty of options, especially for Syria and Iran, that do not involve Israel. HAMAS or Hezbollah might hit Israel, but I suspect Hezbollah is pretty well tied up assisting Assad presently anyway.
There's no need to exclude Russia, though. If we hit Assad hard enough, Putin could, as others have suggested, respond by sinking a British ship in the area. THEN what do we do?
Therefore, I throw out the proposition that Obama launches 37 Tomahawks, lots of empty buildings hit, maybe the Ministry of Defense (empty at 03:00) and a Republican Guard base, no more than that.
He quickly announces that it's all over and let that be a lesson to you Assad...
Putin would sink a British warship? I do not see it as it would require an escalation, something nobody wants.