I imagine even if something like that was being actively worked on, very powerful people would be working day and night to halt it, probably successfully.
Or deliberately leave the job half done and only one quarter working, as in the UK
Let's do it step by step, first let's get rid of all the dictators, there are still a few roaming around
The US's separation of state and federal powers is already kind of that. In addition to lots of countries with similar systems. Maybe I'm misunderstanding you though.