Two Party System

When the vast majority of elected officials are members of one of just 2 key political parties.

A natural (?) outcome of First Past The Post/Majority Representation Voting System.

In the US these are currently the Republican Party and the Democratic Party

One could argue that this results in little real "choice" for the citizenry. A de-facto One Party System

Some say that what's messed up in European politics is due to having more than 2 parties. (a Multi Party System)

http://www.wikipedia.org/wiki/Two-party_system

Why have any Political Party at all?