Does military intervention in Libya comply with just war doctrine?

Thanks to Rick for flagging Michael Walzer's criticism of the West's military intervention in Libya.  I agree with Walzer's concerns, but I wonder if there is a way to ground the case against the intervention in terms sounding directly in the Church's just war doctrine.  For me at least, it was relatively easy to explain my opposition to the Bush administration's invasion of Iraq: there was no showing that a preemptive war was necessitated by "imminent" grave harm to the U.S., and the war's rationale (at least as stated by President Bush) seemed to place a much greater value on American lives than on Iraqi lives.  I also oppose the Obama administration's actions in Libya, but I have a hard time placing "incoherence" within just war doctrine.  Here's para. 2309 of the Catechism:

The strict conditions for legitimate defense by military force require rigorous consideration. The gravity of such a decision makes it subject to rigorous conditions of moral legitimacy. At one and the same time:

- the damage inflicted by the aggressor on the nation or community of nations must be lasting, grave, and certain;

- all other means of putting an end to it must have been shown to be impractical or ineffective;

- there must be serious prospects of success;

- the use of arms must not produce evils and disorders graver than the evil to be eliminated. The power of modem means of destruction weighs very heavily in evaluating this condition.

These are the traditional elements enumerated in what is called the "just war" doctrine.

The evaluation of these conditions for moral legitimacy belongs to the prudential judgment of those who have responsibility for the common good.

If the aim of the intervention is humanitarian, doesn't it fail the "serious prospects for success" prong by merely extending the conflict?  Does just war doctrine speak to this conflict in other ways, or are these factors largely superfluous to a serious moral evaluation of the intervention?