"Oftentimes a third party movement gets swallowed by the party that is closest to it ideologically," says Geoffrey Skelley, associate editor of Sabato's Crystal Ball at the University of Virginia Centre for Politics. "The Democrats got hold of the Populist movement. And Teddy Roosevelt ran as a Progressive in 1912 [on the Bull Moose ticket]."
But while some breathed fresh life into politics, none gained enough heft to rearrange the partisan landscape.
"Third parties are like bees," said historian Richard Hofstadter. "Once they have stung, they die."
In essence, none has been able to overcome the structural obstacles that stand between obscurity and national recognition, hurdles often engineered by the duopoly to maintain what is, in effect, a closed shop.
"If a third-party candidate wants to really make an impact that person needs to be very famous or very rich," says Frank Newport, Gallup's editor-in-chief.
"Ross Perot got 18.6 per cent of the popular vote, which is pretty big, in 1992. He was rich. Teddy Roosevelt did pretty well because he was famous. He had served as President."
Media fame helps; Jesse Ventura, a professional television wrestler who ran as a Reform Party candidate, became Minnesota's governor in 1999.
But even fame or wealth are no guarantee of real impact. America's first-past-the-post system, where the party with the most votes wins, is a major hurdle, even as the duopoly games the system to deter rivals.
"The major parties have written rules in a way that entrenches them," says Skelley. Candidates need deep pockets to negotiate different state rules to register for primary elections.
"There are restrictive rules for getting on the ballot, such as a minimum 10 per cent result in recent elections, which most third parties don't get. The duopoly have rigged the game in their favour." Legislative districts are redrawn every decade after the US Census and gerrymandering seats enforces the status quo.
"It's done at the state level," explains Newport. "Whoever is in charge of the state controls that. In 2010 when Republicans gained the House of Representatives and the Tea Party did well, the state legislatures were controlled by Republicans, who handled the redistricting process."
And while courts may insist districts represent minorities who might fall below the minimum threshold to elect, say, a black or Latino member of congress, political skulduggery remains a potent bar.
"There's no question that, if you look at California after the 2000 Census, the parties worked to institutionalise their seats," says Karlyn Bowman, a senior fellow at the American Enterprise Institute. "They essentially colluded to protect their own districts and incumbents."
This clearly annoys many Americans. A USA Today/Bipartisan Policy Centre poll this week found 35 per cent wanted a bipartisan commission to draw up legislative districts, 28 per cent favoured the state legislature and governor and 22 per cent the state supreme court.
Similarly, expanding the eligible primary vote to include independents is seen as another way to democratise the system and reduce partisanship.
Given the number of Americans who identify as independents - a moveable feast: Gallup's figures this week have 41 per cent, as against 30 per cent Democrats and 23 Republicans - they might seem a perfect base for a stand-alone third party. But US politics are not that simple.
"Independents are almost always supportive of third parties," says Bowman.
"But the number of pure independents is actually quite small."
Most are ersatz independents whose ultimate allegiance is to the duopoly. Skelley calls this a "hidden partisan leaning". As elections loom and public inertia, propelled by the duopoly's institutionalised weight, sets in most independents return to the fold. A University of Michigan study, conducted since 1948, cites 10 to 14 per cent pure independents.
Right now attention is focused on the Tea Party which, confusingly, is not a real party at all, but the right wing of the Republican Party.
Gallup found just 28 per cent of Americans have a "favourable impression" of the Grand Old Party - the worst rating of any party in two decades - as Tea Party zealots seized control, the tail wagging the dog.
The party of Abraham Lincoln, which prided itself as a "Big Tent", long ago lost black support.
Could the Tea Party offer a third way? While just 22 per cent of Americans profess support, this trumps Perot's base. Unlike grassroots protests the Tea Party can exploit structural levers, such as gerrymandering.
It has rich backers like the Koch brothers, energy tycoons. It has regional voter bases and popular champions such as Senators Rand Paul and Ted Cruz. And many share Tea Party concerns about "big government," symbolised by President Barack Obama's Patient Protection and Avoidable Care Act, or Obamacare.
It's just that, on closer examination, many people realise much big government - the military, air traffic control, agencies to curb pollution, promote fresh water or fight disease; it's a long list - is indispensable. At the same time the Tea Party's jihad to destroy government in order to save it alienates many. Interestingly, the far right found a home in the GOP. The far left coalesced around the global Occupy Movement outside Congress.
While a Tea Party run might neuter the GOP, to Democrats' joy, modern history suggests victory is elusive.
In 1948 segregationist Senator Storm Thurmond ran for President on the States' Rights Democrat Party, or Dixiecrats, ticket, winning 2.4 per cent of the vote. In 1968 segregationist George Wallace contested the White House for the American Independent Party and pulled 13.5 per cent. In 2000 Ralph Nader represented the Green Party, winning 2.74 per cent.
Impervious, the duopoly ploughed on.
