"It should be observed here that men should either be caressed or crushed; because they can avenge slight injuries, but not those that are very severe. Hence, any injury done to a man must be such that there is no need to fear his revenge."
Would it surprise you to learn that Niccolo Machiavelli wrote that? No, I didn't think so. Seriously, I would never have thought that you could surprise me with how Machiavellian Machiavelli was, but here you have it.
Slow reading, but full of choice, practical, amoral tidbits like this. Really, it makes sense; if you're going to run a city-state singlehandedly, ruthlessness is not optional.