Or, you do what the democratic party in the US has been afraid to do: Rip the bandaid off, accusations of weaponization of the DOJ be damned. The parent's hypothetical situation is precisely what is happening in the US right now where Garland failed to prosecute, and the entire democratic party was far too afraid of appearing to weaponize the justice system meanwhile the opposition has no qualms about doing so. Yes, the public will view it as entirely partisan but there's no other path forward.
But if you just do nothing at all, eventually the social contract breaks. The cost of the corruption becomes too high and the state fails, or you get a forced regime change.
The day this happens is the day that 90% (or more) of our "leaders" find themselves suddenly in prison.