"Star Wars" -style imperial rule, subjugating all species and cultures, annihilating opposition by meeting it with immediate and overwhelming military might. Culture would be somewhere between Shaolin and Spartan discipline for maximum efficacy. Population and genetic distribution would be tightly controlled. Brainwashing or mind manipulation would not need to be that important. Cloned soldiers is not such a bad idea. See also; "God Emperor of Dune".
It would "work well".