The most important factor in that the Patrician (Havelock Vetinari, as a joke on the Medicis) ensures that almost everyone agrees that his continued rule is mar

The most important factor in that the Patrician (Havelock Vetinari, as a joke on the Medicis) ensures that almost everyone agrees that his continued rule is marginally better than upsetting the status-quo... And in some cases allows opposition to succeed just enough to make people regret it. Part of this rests on the ancient Guild of Assassins, which requires a certain amount of style and also has a very very dim view on anyone threatening their monopoly on killing-for-profit. Their price for going after Vetinari is high enough to discourage most bidders, and Vetinari is a skilled (mostly non-practicing) alumnus that can largely protect himself from them. ______ > “I see you're very comfortable here,” said Vimes weakly. > “Never build a dungeon you wouldn't be happy to spend the night in yourself,” said the Patrician, laying out the food on the cloth. “The world would be a happier place if more people remembered that.” > “We all thought you had built secret tunnels and suchlike,” said Vimes. > “Can't imagine why,” said the Patrician. “One would have to keep on running. So inefficient. Whereas here I am at the hub of things. I hope you understand that, Vimes. Never trust any ruler who puts his faith in tunnels and bunkers and escape routes. The chances are that his heart isn't in the job.” [...] > "You see,” he said, “it’s always the case, is it not, that should a city be overtaken by violent civil unrest the current ruler is thrown into the dungeons? To a certain type of mind that is so much more satisfying than mere execution." > “Well, okay, but I don’t see—” Vimes began. > “And you look at this door and what you see is a really strong cell door, yes?” > “Of course. You’ve only got to look at the bolts and—” > “You know, I’m really rather pleased,” said Lord Vetinari quietly. > Vimes stared at the door until his eyebrows ached. And then, just as random patterns in cloud suddenly, without changing in any way, become a horse’s head or a sailing ship, he saw what he’d been looking at all along. A sense of terrifying admiration overcame him. > He wondered what it was like in the Patrician’s mind. All cold and shiny, he thought, all blued steel and icicles and little wheels clicking along like a huge clock. The kind of mind that would carefully consider its own downfall and turn it to advantage. It was a perfectly normal dungeon door, but it all depended on your sense of perspective. > In this dungeon the Patrician could hold off the world. All that was on the outside was the lock. All the bolts and bars were on the inside. -- Guards! Guards!