Now the United States has had a two-party system from the beginning. This is part of our unwritten constitution, but one that is a necessary result of the written structures that the Constitution put into place. In a parliamentary system, the chief executive is a “congressman.” This cedes a great deal of power to splinter parties, and so it is that splinter parties tend to form. The structure encourages the alliances to form after the voting. Our structure encourages the alliances to form, in the form of parties, beforehand.
In our system, the executive is elected directly, independent of the elections for the legislature. This causes the factions to cluster beforehand, and the alliances come together in major political parties. Sometimes these alliances are pretty stable and at other times they blow apart. When they blow apart, another party forms. I believe the conditions are ripe for this to happen, and perhaps with both parties.
In the history of the United States, all two and a half centuries of it, we have always had two major parties. I think that this is a structural necessity. But those two parties have not always been the same parties—one of the parties can become a smoking crater, and sometimes has. If this were to happen, then that party would soon be replaced by another one. But it is unlikely in the extreme that we could ever have a stable and standing three-party system.
For example, in the era of the Founders, we had the Federalists and the Republicans. Later we had the Whigs and the Democrats. Currently we have the Democrats and Republicans. There is absolutely no reason why one or both of the current parties could not go the way of the trilobite. There are all sorts of reasons for believing that this is actually happening, both to the Democrats and the Republicans. Both parties are deeply divided and/or fractured. This may be a year, in short, when it is possible to vote against the current parties, both of them together.
via Blog & Mablog