The 1840s

In response to the Congressional Black Caucus's attempt to browbeat him into withdrawing from the presidential election, Ralph Nader wrote: "can you imagine if the Abolitionist Party was told not to run against the pro-slavery Whigs and Democratic Parties in the 1840s" ("In a Letter to the Congressional Black Caucus: Nader Asks for an Apology for 'Obscene Racist Epithet' Made at CBC Meeting," July 13, 2004)! Nathan Newman, a dogged defender of the Democratic Party, retorts on his blog:

[I]t's actually not hard to imagine people criticizing the Abolitionist Party -- actually called the Liberty Party.

William Lloyd Garrison, the most prominent Abolitionist in the period, strongly condemned abolitionists running candidates. It wasn't that he supported the Whigs -- the more anti-slavery party -- but that he thought playing spoiler roles was hardly a recipe for recruiting support to the cause.

And the result in 1844 was that the Liberty Party tipped the election to the pro-slavery, pro-war James Polk.

The result was the war with Mexico that pro-slavery Democrats saw as a tool to expand the number of slave states into the Southwest.

So just as the Liberty Party candidate of 1844 tipped the election to a rightwing racist who would launch an imperial war, so too did Nader's candidacy in 2000 tip the election to Dubya and the war in Iraq.

So to answer Nader's question, many anti-slavery people at the time and today see the Liberty Party Presidential candidacies as misguided and ultimately contributing to rightwing government. ("Nader Defends Mexican-American War," July 14, 2004)

William Lloyd Garrison, fearful of "spoiling" the election for the Whig Party? That's very far from the truth. Garrison's principle, if anything, was a radical combination of anarchism and pacifism inspired by faith in the power of non-resistance -- the very opposite of the spirit of small-minded pragmatism at the bottom of today's Anybody But Bush and Nader arguments:

We cannot acknowledge allegiance to any human government; neither can we oppose any such government by a resort to physical force. . . .

As every human government is upheld by physical strength, and its laws are enforced virtually at the point of the bayonet, we cannot hold any office which imposes upon its incumbent the obligation to compel men to do right, on pain of imprisonment or death. We therefore voluntarily exclude ourselves from every legislative and judicial body, and repudiate all human politics, worldly honors, and stations of authority. If we cannot occupy a seat in the legislature or on the bench, neither can we elect others to act as our substitutes in any such capacity. (William Lloyd Garrison, "Declaration of Sentiments Adopted by the Peace Convention," September 28, 1834)

As for the Liberty Party, it, too, played its role in furthering the abolitionist agenda in the United States: "Although its vote never exceeded 3% of the votes cast in a presidential election, the party did further political abolitionism. In closely contested state and local elections, the Liberty party often held the balance of power, sometimes causing major party candidates to take advanced antislavery positions in a bid for its support" (Kinley J. Brauer, "Liberty Party," Encyclopedia Americana). More importantly, one mustn't forget that many Libertymen eventually joined with anti-slavery Whigs and Democrats to form the Free Soil Party, whose members would later became the radical wing of the Republican Party. Out of many seeming failures can a movement grow.

Update:

Mark Lause, a professor of history at the University of Cincinnati, has a webpage that collects many third parties' platforms (from the mid-19th century to the early 20th century): "Insurgent America On Line: 'Third' Party Platforms."