The Three Cornered War

Alpha-Males: You can't live with 'em, but sometimes you can't live without 'em. An alien migration fleet -- 14,000 starships strong -- searches the stars for a new home, its homeworld forever lost. When they finally find planets that can support them, all they have to do is eradicate the pesky human natives, a task they assume is easily within their powers. But Earth's Commonwealth of Worlds isn't about to give up so easily -- even if it has to create and train something it hasn't had for centuries: soldiers!