The Clone Ultimatum by Steven L. Kent.

The Clone Elite: Earth, 2514. Centuries of galactic peace is shattered when an alien juggernaut advances on Earth, wiping out colonies along the way. Outgunned and outnumbered, the Unified Authority resorts to an unstoppable force of its own-the outlawed Liberator clone Wayson Harris and his men, who must win the battle, and the war...or lose all.

The Clone Betrayal: When the military brass try to blame the clones for the decimation of the U.A. republic, Lt. Harris decides to act. A new assignment in a remote arm of the galaxy may be his only chance to save the clones. But as he tries to liberate a planet from an alien technology, he must also convince his brethren to fight the U.A.-with all the firepower they can muster.

The Clone Empire: Exiled on Terraneau after the U.A. set them up as targets for live-fire training exercises, the clones have founded their own empire. And Harris unleashes his rage against the U.A. Fleet, leading an army with everything to fight for, and one thing to die for-revenge.