You have to do it all by the book (Law of War) and avoid a societal collapse. Both deontological and consequentialist. Difficult.
Difficult indeed.
Any plan has to be for the long run and be systematic with a little here and a little there; so it's a damned if you do and damned if you don't scenario.
If you do too much to soon, everything will or may collapse, but if you take too long it will look like nothing is happening