But the real culprit is America's practice of plurality voting, by which candidates win without an absolute majority. In this system, third-party hopefuls can rarely aspire to be more than "spoilers." Worse, the one-third of all voters who are not registered as Republican or Democrat feel pressured to vote against their worst nightmare rather than their best hope.

A simple reform would correct this problem. Instant runoff voting (IRV), which lets voters rank their choices, would allow America to achieve the basic goal of its electoral system – electing the candidate with the most support.

Plurality voting, used by all states in presidential elections, allows candidates to win all of a state's electoral votes without getting an absolute majority of the popular vote. In recent elections, this system has hurt Democrats and Republicans alike. In 1992, Ross Perot took 19 percent of the vote. That support, observers speculate, sapped George H.W. Bush's support, giving himjust 37 percent of the vote and helping Bill Clinton to win with 43 percent. In 2000, Al Gore lost Florida and the presidency by 537 votes to George W. Bush, even as Ralph Nader won 97,488 votes in Florida – more than 181 times Bush's victory margin.

Because the majority can split its vote with third-place contenders and lose, plurality voting forces too many Americans to vote for their second-choice candidate who has the better chance of winning, rather than the one we actually want.

General elections should be a marketplace of innovative ideas, and independent and third-party candidates can prevent them from becoming a showcase for an overly narrow ideological duopoly. Yet such candidates are pilloried for trying to break the red-blue grip and add a fresh voice to the debate.

It is unfortunate that independent candidates must face these attacks when about one-third of Americans are not registered with a major party. Throw in their distorted nomination process, and it becomes painfully obvious why so many people feel frustrated with electoral politics.

If the US used IRV for presidential elections, voters could avoid the currently dysfunctional system and choose their leader by popular vote, by ranking candidates in order of preference.

IRV is an increasingly popular voting method that leading politicians have supported and other countries already use. Prominent leaders from both parties have backed IRV, including once and current presidential contenders John McCain, Howard Dean, and Barack Obama. Ireland elects its president by IRV; London, its mayor; and Australia, its House of Representatives.

Although critics say IRV would be too complex for voters to understand, the process is as simple as deciding among friends where to go for dinner – everyone knows how to rank their preferences. Voting machines and software could be upgraded to handle the new system.

For IRV to spread nationwide, states could adopt the voting method for congressional and presidential races by mere statute. Indeed, Vermont's state legislature may send the governor a bill to adopt for congressional offices this winter. Voters in nearly a dozen cities, including Minneapolis, San Francisco, and Oakland, Calif., have passed IRV ballot measures, typically by a landslide.

By supporting IRV, Democrats and Republicans can defend their majority status at the polls rather than through machinations over access to ballots and debates. Perhaps some fear this system would encourage third parties to flourish, but third-party and independent candidates already are part of the political system, and they are only likely to grow in support given the increasing apathy toward the major parties.

As the presidential primaries draw near, all eyes are on the major party frontrunners as they stump across the nation to raise money and harvest votes. But some of the biggest 2008 headliners may be quietly waiting on the sidelines. Challengers to the duopoly may well come from the left and the right, meaning that both parties may have at least one fit of anxiety before next November.

Perhaps by 2012, Americans will have decided they want a system that allows them to vote their consciences instead of their fears. Instant runoff voting is one choice voters are sure to embrace.

Former Illinois Congressman John B. Anderson was an independent candidate for president in 1980 and is chair of FairVote, a nonpartisan electoral reform organization based in Maryland.