The United States of America is largely dominated by two political parties, Democrats and Republicans. However, there are many smaller political parties, like the Green Party and the Libertarian Party. So why have the only presidents over the last 170 years been either Republican or Democrat?
IB History of the Americas teacher, Danielle Schwartz explained that when America was first formed, the government split into two factions. Part of the reason it’s still like this is because the two current political parties have too much power. What Schwartz is explaining is a duopoly which is when there are only two large competitors in a market; for example, Coke and Pepsi have a duopoly in the soda market.
The main reason behind the two political parties is Duverger’s Law, theorized by the French political scientist Maurice Duverger. This law points to a few factors.
One of the factors why small parties cannot grow in the American system is that voters may fear their votes canceling out if they did vote for a small party. People may think if they vote for a third party, it does not matter because they won’t win anyway.
Small parties also cannot grow bigger because of the way the USA elects the House of Representatives. If a given state has 10 districts, it will send 10 people to represent the state; if the same state is 60% Democratic and 40% Republican, the state will send 10 Democratic representatives because it is a winner-take-all system in almost every way.
These effects can be seen in the real world, the House of Representatives has no seats that are not Republican or Democratic right now. Throughout America’s history, there have been many political parties, but there have never been three major parties for a long time.
Schwartz said that it is possible for a third party to become a major party but will have to overthrow the Democrats or Republicans to do so.
