FairVote (fairvote.Org) has proposed a form of proportional representation that is constitutional, consistent with the history of American elections, and is based on voting for candidates rather than political parties. States still have their own congressional delegations, but rather than electing them from single-seat districts, they elect up to five of them at a time using ranked choice voting (in a form commonly called "single transferable vote"). That would give us fair results, reduce gridlock, and enhance competition nationwide. It would not require a constitutional amendment, and it has been used by local governments in the U.S. For a century.
Check out this video explanation of it: http://youtu.Be/vS62N5b5L7Y
What would be the costs and benefits of implementing the system of Proportional Representation? I am unsure if it would be a better system then what we have in place today. Proportional Representation works as 100 members in the senate and then have three parties, Party A which is 37% of the vote, Party B which is 30% of the vote and then finally Party C is 33% of the vote.
First let me start off by saying we, in most of america, are on a single-member-district-plurality. With the exception of I believe Nebraska and one other state, most states are on that SMDP system mentioned before. The winner take all system can create pre-election coalitions. For instance say Party A was supposed to get 40% of the vote, Party B 30%, Party C 20% and Party D 10%. The pre-election coalitions are made because of the want to win so Party A might form a coalition with Party D in order to get to 50% just like Party B and C might form one to reach a similar percentage. Proportional Representation is basically what it sounds like. If there were 10 people voting in an election for let's say 4 different parties, then if Party A got 40% of the votes then it would receive 4 people to represent that county or place. Say the 2nd place party got only 30% of the vote then they would get 3 people to represent them and so on so fourth. While it does discourage coalitions within parties and results in fewer votes wasted, it does lack the stability in order to pass legislation at a reasonable time and can slow down the movement of government. I believe it leaves more room for radical parties to have shots at taking over such as the communist party. An example of a proportional representation could be in the early to middle 20th century. They were in shambles following a war and a minor party managed to accumulate enough votes to obtain about 3 seats. With those seats they were able to gain enough influence to capture a larger sum of seats in the next election. Eventually it became a sort of monopoly with government and this party had complete control and was able to do as it pleased based on the majority. That party became known as the Nazi Party. In theory proportional representation offers a more democratic means of self-governance but lacks the foundational structure to sustain itself without poor influence.