There's so many nails on Obama's Presidency's Coffin that it looks like a porcupine already.
Let's consider the options available as of a few days ago;
1: Let thousands or tens of thousands of Libyans, a substantial group of whom are begging for aid, get slaughtered by a dictator, while the world blames us for not helping. How could we have such a double standard, helping Iraq but not Libya?
2: Go it alone into Libya, get stuck in a quagmire, and end up fighting four occupational wars. While the world blames us for imperializing all over the place just like Hitler always wanted to do; those Americans, how dare they not learn from Iraq?
3: Get international permission and then act immediately on an (at least initially) limited basis, making it clear we aren't there to stay, and plan to leave ASAP. The World says Meh, the Europeans say At least they asked this time, and we're helping, China and Russia are Grumpy and the Republicans Threaten to impeach the president, just like they do every night.
Look, I don't like the expense. I don't like the risks to US soldiers. I don't like the glorification of war. But at the moment, and so long as we keep even remotely close to the plan, this "intervention" will probably be the closest to a positive outcome we can get out of this. It would have been better if we'd started sooner, but at that time, it looked like the rebels could win on their own.
TL;DR:
Damned if you do, Damned if you don't, we chose neither and just got Darned.