Radical Partisanship in American Politics

Radical partisanship in American politics is a function of this being a two-party system. In multi-party systems these the level of hatred is generally lower because the enemy isn't as clear, you know, they have to form coalition governments. If we had multiple parties then the kind of core of the of the Republican Party would be its own extremist right-wing fridge party and it would get 20% of the votes in every election.