Many people in the US seem to view our constitution as being some sort of a sacred nearly perfect document with few remaining major flaws. But reality severely defies this supposition. Among our constitution's flaws is the fact that it is designed, albeit accidentally, in such a way as to only support 2 parties at once. This is ensured by the fact that most elections in the US are winner takes all, and people always have to vote for individuals and never parties. This means that the minority votes in any race is given no representation. Because most elections, including those for president, have no run-off rule, by splitting the vote third parties prevent the most widely preferred candidate from winning. Many people are justifiably therefore reluctant to vote for third parties because they are afraid that doing so could lead to their least preferred candidate getting elected. This happened in 2000, where third party green candidate Nader stripped enough votes from Gore in Florida to land George Bush an electoral victory and we all know the consequences of that. Unfortunately, a diversification of the US party system would require fundamental constitutional changes for which there is presently no momentum towards implementing. Perhaps this is in part because the present system suits the benefiting two parties just fine. The US constitution was created 200 years ago before a massive wealth of salient data on the history and characteristics of differing modern republics became available. Its design suffered as a consequence, but we are stuck with it because of patriotic delusions of its merit and because constitutions are especially hard things to change legally. Those who want third parties to succeed in America should advocate constitutional change. There is no other way out of our present predicament of hosting an unchanging duopoly.