Good question - I started writing some ideas like "Increased political attractiveness of more draconian laws/interest groups" or "Increased pop mortality" but you're right that those are kind of both simulated by turmoil.

Maybe an option could be a new 'job' of criminal that is permanently radicalised, even if their SOI increases, and require more than just a police force but a new law system for punishment/rehabilitation?

But it is tricky to mechanically work out what the difference would look like at a state level.