Why Only Two Parties in the US, But Nine in Norway?

How the US voting system reduce the number of parties and how voting systems in other countries give more selection to voters.

The Norwegian Parliament. It has 169 representatives of which 150 are selected from Norway’s 19 provinces.

Why is it so difficult to vote a third party into power in the US? This isn’t simply a cultural phenomenon. Almost every time I see a discussion of this in social media it seems as if Americans believe it is caused by an attitude problem among Americans themselves.

People tell each other that you need to stop voting Democrat and Republican and give a third party a chance. But it is not an attitude problem. American voters are simply responding logically to the incentives built into the voting system. I will try to explain how in Norway we have ended up with nine different parties represented in parliament. To understand such different outcomes we have to compare how voting works in the US and in Norway.

Some of the biggest political parties in Norway. From top left to bottom right: communists, socialists, labour, farmers party, christian party, liberals, conservatives, low taxes and anti immigrants party.

Please note that there is nothing unique about the Norwegian system. It is similar to voting systems found in the Netherlands, Austria, Germany, Sweden, Denmark, Finland and many other countries.