One bid to mount a serious third-party challenge in the 2012 presidential elections cleared an important hurdle Tuesday.

Americans Elect, which intends to hold a nonpartisan nominating convention online and put the winner on the ballot in all 50 states, earned a spot on the California ticket.

The nonprofit group has already won ballot certification in 11 other states – including the swing states of Florida, Michigan, Nevada, Ohio, and Colorado. And some political analysts say that a confluence of factors – ranging from the weak economy to growing voter dissatisfaction with the two main parties – could lead to a third-party candidate potentially having a major impact.

“The old adage is that third-party candidates act only as spoilers and make people mad with no chance to win, but this year may be different,” says Barbara O’Connor, director of the Institute for Study of Politics and Media at California State University, Sacramento.

Not only has voter angst created fertile ground for a third-party appeal, there has also been a rise in the number of voters who don't identify themselves with either major party.

“They [Democrats and Republicans] have their work cut out because voters really deeply feel that the two main parties have not functioned, and people are tired of it and ready for the rise of a third party,” says Ms. O’Connor.

Some third parties develop around personalities – such as Ross Perot, Teddy Roosevelt, John Anderson, or George Wallace – who rally disaffected supporters from the Democrats or Republicans around an agenda ignored by both of the major parties. Others, like Greens and Libertarians are more ideological and endure from election cycle to election cycle.

“The problem for Americans Elect is they are neither personality-centered nor ideological,” says Villanova University political scientist Matthew Kerbel. “They are about process – about using the Internet to select a candidate. To that end, getting on the ballot in a large state like California is an accomplishment. But it is a triumph of process with no predictive value for the influence they may have next November.”

That is, unless a charismatic or well-known leader emerges from American Elect's online nominating convention.

“The impact of Americans Elect will depend on the nominee. A well-known candidate might win a measurable share of the popular vote,” says Jack Pitney, professor of government at Claremont McKenna College.

And that would almost certainly change the political calculus.

“A reelection campaign is a referendum on the incumbent, so anything that splits the anti-Obama vote will work to the president’s advantage," says Mr. Pitney.

Noting that Ralph Nader siphoned enough votes from Al Gore to tip Florida – and thus the presidency – to George W. Bush in 2000, analysts say that third party candidates usually hurt who they are closest to ideologically.

“Anyone to the left will take from the Democrats and hurt Obama and to the right will hurt his opponent,” says Jessica Levinson, former political reform director for the Center for Governmental Studies.

Still others think that this particular election is so polarized, it might make voters loath to give up their votes at all.

“The more Democrats and Republicans believe that the other party is not just wrong, but evil – as seems to be likely the sub rosa messages of both parties' campaign strategies – then the less likely voters will vote for a third-party candidate,” says Villanova political scientist Lara Brown, author of “Jockeying for the American Presidency." "I don't imagine that when election day rolls around too many voters will feel they can waste their votes.”