>>18131767
>>18131773
>completely contrived rules like that
The only rules necessary for a multi-party system are that votes aren't thrown away and coalitions are possible. Not at all contrived. If anything, throw-your-vote-away systems are contrived.
Also there are parties orthogonal to the common left/right divide in europe, for example the danish social democrats and some german leftists (BSW) are anti-immigration, polish conservatives are pro-welfare, stuff like that. It's not common because left/right actually describes most people's opinions pretty well. Either way, the existence of multiple parties makes it easier to bridge the gap with a central party, or differentiate within a camp if you find some new topic important. For example, the green parties that sprung up in europe a couple decades ago to enforce more environmental protection.