I have a passing familiarity with the politics of a couple countries, and they all fit this pattern: their constitutions say nothing of a two-party system, they don’t even say anything about parties at all. People just choose to create political parties, and then those parties coalesce into two major parties.

The reason that this happens is because people, from voters to every level of politician, look at the rules of the game and make tactical decisions; their tactical decisions cause a two-party system to emerge.

The USA is a really extreme case of this; in Europe there are more parties, and they even very occasionally come to power. Current french president Macron broke a decades-long streak of two-party governance in his country.

Further viewing material:

What is tactical voting

Minority Rule: First Past the Post Voting

The Alternative Vote Explained

My takeaway from this is that there are things that can be done to improve the voting system, as suggested in these videos; but i don’t even like representative democracy at all, i think there’s better solutions in direct democracy (referendums and such). Representative democracy was designed to put elites in charge, voting was initially reserved for land-owning nobility. Extending voting rights to more people doesn’t change what the system is designed to do.