Well thats another interesting thing. Is your system as a whole capable of dealing with that? The u.s system is in the face of difficult social and economic issues, either designed to be deadlocked or a lot of people get left out in the cold of effective federal legislature.
Last time a 'progressive' (I don't agree with that term but for the sake of keeping things simple) agenda was in the ascendency, certain people decided the union might not be for them.
Also one party to rule them all, where every ambitious person has to wait in a line, the average waiting time for which might be longer than the average human lifespan. That might not last forever.