I don't buy that as a general principal. You get the odd fascist leader of democracies that wants to do that in say Hungary, Turkey, even the US got a whiff of it. But most people and most politicians actually like democracy and support the ideas around it, they want to be left along and live in peace and prosperity. Pols want power and to crush the other political side in parliment, but ending public dissent is not the plan of most political parties or politicians.
the people and entities in power
>what's the mechanism against that?
disarming the population