The Strategy of Sowing Discord
Undermine your enemy's ability to fight by secretly causing discord between him and his friends, allies, advisors, family, commanders, soldiers, and population. While he is preoccupied settling internal disputes his ability to attack or defend, is compromised.
Years ago, I used to work in a help desk environment. The lead help desk support technician was always worried that he would be replaced. I don't know why; it wasn't that kind of environment at all. In fact, if people ever left, it was due to promotion or higher pay elsewhere. But because of his paranoia, he conducted a stealth campaign of disinformation that would have done the old Soviet Union proud. He would praise your work to your face. Then he'd tell a colleague of yours that your work was no good. While you were attempting to fight off the rumors and innuendoes that he'd make up, he'd be schmoozing with his boss, but mostly his boss's peers. Then he'd tell you about job openings that were available for you in other companies! His scheme backfired only because his boss didn't trust him any farther than he could throw him. I solved my problems with him by leaving for a job that paid me $20K more.