In recent decades, no independent candidate has mounted a credible challenge for a statewide office in Pennsylvania. And unlike the 2000 presidential race in Florida, it's hard to make a case that any third party on the ballot has influenced the outcome of a statewide contest in recent decades.
But in this year's race for governor, the lineup of candidates who have apparently qualified for the ballot suggests a scenario that could, in a tight race, hurt the Republican front-runner, Attorney General Tom Corbett.
In addition to his Democratic opponent, Allegheny County Executive Dan Onorato, the ballot will include Marakay Rogers, the Libertarian Party candidate, and John Krupa, running under the banner of the tea party.
Libertarians tend to diverge from the current Republican Party on social issues. Tea Party supporters criticize both major parties. Still, it's at least broadly accurate to say that both of those constituencies, with their common opposition toward bigger government, are more likely to overlap with Republicans than Democrats.
Current polling -- Mr. Corbett's lead has hovered around 10 points in recent surveys -- and the state's political history suggest that the potential for those candidates to siphon votes represents more of an irritant than a significant threat to the Republican. But should the race tighten in the coming weeks, that could change.
Mr. Krupa's candidacy is a particular wild card, as it is the first time anyone has run under the tea party name in a statewide race in Pennsylvania. The movement is diffuse and multifaceted, however, and Mr. Krupa's ballot label does not mean that the various tea party groups have anointed him.
Earlier this year, Mr. Krupa, of Clinton County, had planned to run under the identification of the Constitution Party, according to the website of the party, which is a grass-roots conservative group opposed to the Obama administration.
Mr. Krupa could not be reached for comment. But some tea party activists are wary of his candidacy.
"The Pittsburgh Tea Party Movement is the largest tea party group in Pennsylvania and you would think John Krupa would have had the courtesy to contact us to put himself on our radar screen if he was going to legitimately use the tea party name," Patti Weaver, a key organizer of the local group, said in a e-mail. "I have never heard of John Krupa and don't know anything about him. While our organization does not endorse anyone, I, personally, would say, 'Don't vote for him.'
"I have spent a year and a half as a volunteer developing the tea party name and John Krupa is hijacking it," she added.
Today is the deadline to file legal challenges to the petitions of independent candidates. Each had to submit nearly 20,000 signatures of registered voters to secure a spot on the ballot, a number based on the total votes cast in the last statewide election.
Spokesman Kevin Harley said that Mr. Corbett had no plans to challenge the petitions of either of his two new rivals, but added, "I assume the state party is doing its due diligence."
Mike Barley, a spokesman for the state GOP, said the party had no plans to challenge any petitions.
But GOP figures have complained loudly about what they characterize as Democratic gamesmanship with petitions in two adjacent Philadelphia suburban districts, the 7th and the 8th. In both, they charge that Democratic operatives worked to secure signatures for independent candidates to siphon votes from Republican U.S. House nominees.
Ms. Rogers, the Libertarian contender, said there are plenty of reasons for independents to run that have nothing to do with political mischief.
"The mere fact that you might not win or probably won't win is not an excuse for not running," said the York County lawyer. "The fewer candidates that run, the fewer ideas that will be discussed -- the vote for women, Social Security -- and those were originally third-party ideas. If third parties didn't raise the issue first, the other parties would never adopt them."
Ms. Rogers is a veteran tilter at the major party windmills. She ran for governor as a Green Party candidate in 2006. After migrating to the Libertarians, she ran for attorney general in 2008 and for Superior Court in 2009.
Her short-lived Green Party candidacy coincided with one notorious case in which a third-party candidacy became a proxy war between the major parties. Carl Romanelli of Wilkes-Barre was the party's U.S. Senate candidate in an election in which Republican Sen. Rick Santorum was being challenged by Democrat Bob Casey Jr.
Complaints of outside meddling were heard first when normally Republican contributors helped fund Mr. Romanelli's petition drive. The fluctuating signature threshold, based on the highest vote total in the preceding election, was particularly daunting that year at roughly 67,000. Mr. Romanelli managed to submit nearly more than 90,000 names, but the state Democratic Party successfully challenged the validity of enough of them to have Mr. Romanelli thrown off the ballot.
Evidence in the ongoing Bonusgate prosecutions, being conducted by Mr. Corbett's office, suggests that much of the work in scrutinizing his petitions was done by Democratic legislative employees. Mr. Romanelli filed a federal lawsuit this month demanding more than $300,000 in damages from the state party and various Democratic figures, including former Speaker Bill DeWeese.
Bonusgate testimony also has suggested that Democratic legislative employees played a crucial role in finding enough invalid signatures to have Ralph Nader's name struck from Pennsylvania's presidential ballot in 2004.
In 2004, Sen. John Kerry won Pennsylvania's 21 electoral votes over President George W. Bush, with fewer than 150,000 votes separating them out of nearly 5.8 million cast.
While he ran again and received only 44,000 Pennsylvania votes in the Obama landslide of 2008, it is conceivable that Mr. Nader could have pulled enough votes in 2004 to have tipped the state's electoral votes to Mr. Bush, sparing the nation a long night while Mr. Kerry decided whether to challenge the Ohio victory that secured Mr. Bush's re-election.
Mr. Nader was arguably the most consequential third-party candidate removed from a Pennsylvania ballot.
Peg Luksik, who was an unsuccessful candidate for the GOP Senate nomination this year, is the champion vote getter among third-party candidates in recent decades. Ms. Luksik, running as the Constitution Party candidate for governor in 1994, attracted 460,000 votes, a total that was more than double the 200,000-vote difference between the winner, Republican Tom Ridge, and Democrat Mark Singel.
The state's closely watched U.S. Senate race also has drawn third-party contenders this year, but their presence doesn't seem to be a big plus for either of the major party candidates. Douglas Jamison filed papers to run as a Libertarian, and, from the left, Mel Packer is the candidate of the Green Party.
Politics Editor James O'Toole: email@example.com or 412-263-1562.