The political system of the United States of America has resulted in effectively a two-party system. This is a natural occurrence in a first-past-the-post system, where each candidate stands in a single-seat constituency and the candidate with the most votes wins the seat outright. But this can lead to an assembly that doesn't reflect the voters' overall preferences particularly well. It has led some to suggest that the system should be changed to a proportional system. So, how would American politics look under a proportional system? It's time for a thought experiment. The Dutch offer an example of such a system. The Netherlands House of Representatives, which started in 2002, is elected based on an open list. Voters give their vote to a candidate on the list, but what's important first is what party that candidate represents. The House has 150 seats, and under the Dutch system, a seat is awarded to a party for every one hundred and fiftieth of the popular vote. Inevitably, this will not lead to every seat being filled, so the remaining seats are awarded based on the highest remainder. There is one small caveat in the Dutch system that we won't be applying here without overview analysis, but it's worth mentioning. Any individual who gains one quarter of the threshold in votes in their own right is considered elected, jumping the list put forward by their party and resulting in the presence of independent members. Applying the system of proportional representation to American politics will require some assumptions. The third most popular party in America is the Libertarian Party, which received just 1.2 percent of the popular vote for the House of Representatives in 2014. Compare this with the United Kingdom's 2015 election result, where the third largest party, UKIP, received twelve point six...