Originally Posted by ElvisManson

The Electoral College, and single member districts in Congress, help support a two-party system by making it less worth while for minor parties to run and making it less likely people will donate money to a party with little or no chance of winning anything.

Compare our system to any of the multi-member district system in Japan, Italy, France, etc. They end up with a multitude of parties making it hard to form a majority government. In the 20 or 30 years after World War II, Italy averaged a new government every year.

The few third parties that got started here (Populists in the 1890's and American Independent in the 1960s's and 1970s) ended when one of the major parties adopted their ideas. With this ability to influence the major parties' positions without destabilizing the government, it is not really an oligarchy. The leaders are not immune from the ideas and demands made by minor parties