Deal with the Devil - Cocytus, #3

The Ipis believed they had exterminated or enslaved all humans in the galaxy, unaware until recently that the star travelling humans had united behind a new leader, Dante Carloman and that a technologically backward planet called Earth, filled with those hated humans, existed on the fringe of their empire. Standing before the American President, Elizabeth Stevenson, Dante recalled an earlier conversation with his commanders: One general told him bluntly, "You'll have to get the Earth to join our side fast or I'll be overwhelmed, no matter what tactics we use." "I'll find a way.
I have to." Another sighed, "All we have to do is depend on a relief armada from an alliance that didn't exist a year ago, unite a human population that has never agreed on anything since we crawled out of the swamp, and bust up an enemy that hasn't lost a significant battle in over a hundred and twenty years." President Stevenson sniffed. "These aliens kill at will, without remorse, wherever they want.
And there's not a thing I can do about it. I'd make a deal with the devil for a chance to save lives." Dante glanced at the sky. "You'll have to. When what we call the harpies attacked you a few weeks ago, the Earth was irrevocably changed, and countless millions died. You have no more chance to maintain your lives as they once were than the Caribbean islanders did when they encountered Christopher Columbus."