Winds of change: The UK's third party sets an example for the U.S.

Both efforts tried to seize on dissatisfaction with the economy and a system driven by partisanship. Neither had a leader dynamic enough to succeed. Both also rejected ideological extremes that were seen as too rigid and out of touch. Today, strong reassertions of ideological extremes are taking place in the Democratic and Republican parties; witness conservative and liberal primary challenges arising against incumbents. While the country is moving to the center and record numbers are registering as independents, the Republicans are effectively being driven, and pressured, by Sarah Palin, and the Democrats by MoveOn.org.

Several factors could trigger the growth of these kinds of movements here. The Supreme Court has made it easier to launch massive paid political advertising campaigns; the Internet has made it possible to mobilize millions of voters quickly. From Connecticut to Pennsylvania to Florida to Utah, the pattern is emerging that when the left or right extremes mount a primary challenge, the incumbent can move outside the party — and win. More and more candidates, especially self-funders, are considering the independent option.

There is also a structural problem — socially liberal and fiscally conservative voters believe, especially after what happened with health care, that they have no clear choice: They must sign on with the religious right or the economic left. It is just a matter of time before they demand their own movement or party.