Another aspect of the Libyan intervention that's triggered much wringing of hands and gnashing of teeth is the precedent it may or may not be creating. "Does this obligate us to intervene whenever there is some sort of ongoing atrocity? Does this obligate us to intervene wherever a dictator rules without the consent of his people?"
The answer to both questions is clearly no. The timeline of events preceding the Libyan airstrikes should make clear that intervention was the result of balanced interests. In the weeks preceding the attacks, the cost of intervention declined. More and more international support built behind the idea, including UN support and Arab support. Qaddafi presented clear military targets that could be destroyed from the air. It seemed increasingly obvious that Qaddafi could marshal very little support from the Libyan people themselves, and was forced to rely on mercenaries hired with oil profits. A number of nations seemed willing to commit forces. Meanwhile, the benefits of intervention increased. The rebel cause seemed more and more hopeless. The stakes were raised from Libyan liberty to many Libyan lives. The revolutions across the Middle East continued and even accelerated, and governments were increasingly emboldened to respond to those revolutions with force. Finally, the balance tipped.
Of course, this multifactorial approach leaves open the question of precedent. The answer is admittedly unclear. It doesn't seem like any consideration trumped all others, which is reasonable enough -- if leaders adopted a blinkered, one-dimensional doctrine for intervention, the free world could find itself dragged into otherwise untenable conflicts. But as any law student knows, balancing tests are difficult to predict. Which conflicts will we intervene in in the future? It's hard to say.
But that's not entirely a negative.
One of the clear advantages of intervention in Libya is that it proves that there is a line in the sand that dictators shouldn't cross. It demonstrates that killing one's own people might have consequences somewhere down the road. That's useful in the immediate future -- Qaddafi most assuredly isn't going to be the last Middle Eastern dictator with the opportunity to conduct a massacre this year -- and further down the road.
This is an objective which benefits from a certain degree of ambiguity. If the UN or NATO or the US were to lay out some explicit set of preconditions for military intervention, a dictator could try to carefully walk that line, killing just few enough people to avoid an international response. Doubtlessly, some will still try to do so. But fuzziness over where, exactly, the line lies will hopefully create an incentive to err on the side of caution. And there's something to be said for any ambiguity which makes kings and tyrants think twice about unleashing fighter jets on crowds of peaceful demonstrators.