Do, or do not. There is no try.
This is only a slight oversimplification of my biggest problem with Obama's offensive in Libya. If we're going to intervene in Libya, then damn it, make sure the job gets done. Don't just lob a few cruise missiles and hope for the best. Make change, oh light-bringer!
But if we're not going to go all the way, then don't bother.
(2) Having recently read the War Powers Resolution for the first time, I am starting to grasp the controversy surrounding it. I think the general idea of a war powers resolution is probably Constitutional, but I have doubts about specific provisions in the current document.
Generally speaking, I think Obama's actions in Libya are most likely Constitutional, though I am amazed by the naked hypocrisy of those like Joe Biden, by whose standards Obama should be impeached.
(3) If we are to be the world's policemen, where does it all end? How do we decide where to get involved? Why Libya and not Bahrain?
My answer: Supererogation. If we are to use a humanitarian justification for intervening in Libya, that does not obligate us to intervene everywhere. It should be plain that the US literally can not be the world's police force. Therefore, injecting the Kantian principle that "ought implies can", we are not obligated to police the world. But that should not preclude supererogatory intervention in certain circumstances of our collective choosing.
How are we to decide which cases? A capital-C Conservative answer might be when it is in the US national interest to do so.