Overrated:
Ralph Nader, Green party, 2000. Hold on, now! Didn’t he cost Al Gore the presidency? Didn’t he change the course of modern political history by, in essence, splitting the Democratic vote and delivering the White House to George W. Bush? How can such an influential candidate be overrated? Well, because he did nothing of the sort. What’s more, his 2.74 percent of the vote was pretty abysmal, compared with some other third-party candidacies, such as Ross Perot’s in 1992 and George Wallace’s in 1968. By their standard, Nader’s campaign in 2000 is less than a footnote in political history.

Gore's supporters and neutral pundits argue that, if Ralph Nader hadn’t been in the race, his supporters would have voted for Al Gore and so, given him the votes he needed in Florida and elsewhere. But that’s highly debatable. Many of Nader’s true believers would have simply stayed home or would have voted for another marginal candidate (such as the Reform party’s). After all, Nader argued that there was little difference between Gore and Bush, so it requires a bit of a leap to believe that his supporters would have backed Gore in Nader’s absence.

Unlike many other third-party candidates, Nader did not inspire a reform movement with his 2000 campaign; nor did it help shape the nation’s political conversation. Embittered Democrats give Nader and the Greens far too much credit.

Underrated:
The vote here goes to Theodore Roosevelt, who ran for president on the Bull Moose party line in 1912.

If you’re looking for a third-party candidate who really did influence a national election, TR is your man. It’s certainly possible that the incumbent president, William Howard Taft, a Republican, might have lost to the Democrat, Woodrow Wilson, anyway. But, with Roosevelt in the race, Taft became little more than an afterthought, an amazing scenario for a sitting president running for re-election.

Roosevelt’s success can be measured in raw vote totals and in ideas, surely the mark of a successful third-party candidate. The Bull Moose party stood for the direct election of U.S. senators, women’s suffrage, aggressive conservation of natural resources, initiative and referendum, and—hello, Arnold Schwarzenegger—recall. Quite a legacy.

The numbers were pretty impressive, too. Roosevelt finished second to Wilson with 4.1 million votes. And poor Taft - the incumbent, no less - managed just 23.2 percent of the popular vote.

Aside from beating a major-party candidate, Roosevelt and his fellow Bull Moosers had a profound impact on local and national politics. Prominent reformers put the party’s platform into action, and the Bull Moose legacy is with us still. Not bad, for a “minor” party.