At least in parliamentary systems, in order to be able to form a majority govt, a party usually has to make back-room deals with the smaller, single-issue parties (think green or pro-life). Then, when forming policy around these particular issues, the administration has to promote/follow a much more extreme position than reflects the more mainstream party or the majority of the population.
so a small minority of people end up wielding much more relative power.
Im not sure how it would work in our system. I suppose that you could say that it forces compromise — but perhaps it is not much different than the far-left wing of the Democrats or the far-right of the GOP and all the “congressional caucuses” they’ve created.
