Why are political parties an important example of unwritten constitution?

Having three different political parties allows the voters to have three very different choices which is an unwritten part of the constitution but is what the constitution wanted when it was written. Each party has very different views on how our country should be run and this allows the people to make a choice and then the electoral college helps to make a decision in the case of he presidential election. Otherwise in an election it is done by majority rules where each voters vote is equal to the next persons vote.