All representative democracy give us is the ability, collectively, to sack a government that has outlived its welcome for some reason. (What happens after that is a complete crap shoot.)

When opposition parties start to triangulate -- that is, to define their policies in terms of what the government and perceived extreme opposite are doing -- rather than by espousing a concrete ideology or policy platform, we end up with everything converging on one dominant faction's idea of how to do things: a one party state in all but name.

(Which seems to be where we are here in the UK right now, and to a lesser extent in the USA.)