As long as we're kicking around abroad...
My politically incorrect view is: As long as we're intervening in countries like Afghanistan (Cold War), Iraq, potentially Iran (it's clear the government wants to go there), and elsewhere, why not intervene in Darfur? At least they actually need it.
My politically correct view: As one of the most--if not the most--powerful nations in the world, we have the resources and the obligation to intervene on behalf of the victims of this genocide (and all others). We had information about Hitler's annihilation of the Jews and didn't act on it--look what happened there! We have far more extensive, and far more concrete information about the genocide in Darfur... so why won't we do anything?
They don't have resources we need, that's why. (Yes, that's the cynical view.)
If America wants to set an example for the world--peace, love, whatever--we have to intervene. More than that--by turning a blind eye to the genocide, we are no better than the killers.