People want a third party. Until they don’t.

One look at the deep dissatisfaction coursing through the American electorate — record disapproval numbers for Congress, President Obama at the lowest ebb of his time in office — and it becomes clear that a desire for something/someone else in politics is as strong as it’s been since, at least, 1992.

(Is it time for a Ross Perot-like candidate to emerge in 2012?) Columnist Matt Miller put voice to that sentiment in a piece over the weekend entitled “Why we need a third party”.

Wrote Miller:

Why should we have to choose between timid half-measures and anti-tax fanaticism? Why doesn’t the president propose measures equal to the scale of our challenges? Why can’t Republicans acknowledge demography or math?

That frustration/desire for something new is born out in a series of national polls conducted over the last few months.

One in three people said the two party system is “seriously broken” and the country needs a third party in a late August NBC/Wall Street Journal poll. In an April 2011 Gallup poll, 52 percent of respondents said that the two parties do such a poor job that a third party is necessary.

Couple those numbers with the dissatisfaction with President Obama among the Democratic base, the ongoing — and seemingly endless — search for new candidates in the Republican presidential field and efforts made by outside groups to win ballot access for a third party candidate in 2012 and it seems like a no-brainer for someone to leap at the opportunity.

But, no one has. Why not?

Largely because while the idea of a third party candidate is appealing in theory, it’s far less viable in practice. (In the immortal words of Homer Simpson: “In theory, communism works.”)

Everyone, in theory, likes the idea of more choices in politics (and in life.) That’s especially true when the two parties are viewed as negatively as they are at the moment.

But, when an actual candidate is floated as a third party option and the question goes from theoretical to practical, it’s a very different story.

One example: In a December 2010 Washington Post/ABC News poll New York City Mayor Michael Bloomberg, who is viewed as the most viable 2012 third party candidate, was included in a three-way ballot test with President Obama and former Alaska governor Sarah Palin. Obama took 47 percent to 31 percent for Palin and 18 percent for Bloomberg; that’s not an embarrassing showing for the Mayor but it is a reflection of the challenges of running outside of the two-party system.

Inherent in the disparity between the number of people who like the idea of a third party and those who would vote for a third party candidate is that we, as human beings, like winners. Or we at least like the idea that our vote matters.

Unless and until a third party candidate can prove that he/she is a genuine contender and not simply a spoiler — ala Ralph Nader in 2000 — no one but pure one-issue voters (or those deeply disenchanted with the two party system) will be willing to, in effect, throw away their vote.

Remember that Ross Perot, by far the most credible third party candidate in modern political memory, failed to crack 20 percent in either of his two presidential runs in the 1990s. (He won 19 percent nationally in 1992 and eight percent in 1996.)

The other thing to consider when analyzing the chasm between the idea of a third party and the actual support for a third party candidate is that when the conversation stays in the purely hypothetical realm it’s easy for people to imagine their perfect candidate — someone who could fulfill the hope and promise people (still) have for politics.

When an actual candidate emerges, that person’s warts become apparent and turn off lots of people who, in theory, like the idea of voting for someone outside of the two party system.

Given those realities, it’s a near-certainty that a third party candidacy will remain in the hypothetical realm in 2012 — and likely beyond.

Read more on PostPolitics.com

Who is straw-poll winner Herman Cain?

Obama to Democrats: Get pumped up

Senate hopes to pass spending bill, but that won’t avert government shutdown