Alex Wong / Getty Images Former Democratic gubernatorial candidate for Virginia Terry McAuliffe speaks during a campaign rally on Nov. 4, 2013 in Annandale, Va.

Even before yesterday’s election, Republicans were ready to blame Virginia gubernatorial candidate Ken Cuccinelli’s looming defeat to Democrat Terry McAuliffe on Libertarian Party candidate Robert Sarvis. “A Vote for Sarvis is a Vote for McAuliffe” argued one Cuccinelli supporter.

With the final count in, expect Republican anger at the Libertarian “spoiler” to grow exponentially. McAuliffe, who had enjoyed a double-digit lead at various points in during campaign, won with just 48 percent of the vote to Cuccinelli’s 46 percent. The Libertarian Sarvis ended up pulling almost 7 percent, far more than enough to tip the election the other way.

But to blame a major-party loss on third-party candidates is fundamentally mistaken. First off, it ignores data that the Libertarian pulled more votes from the Democratic candidate than he did from the Republican one—an exit poll of Sarvis voters showed that they would have voted for McAuliffe by a two-to-one margin over Cucinelli. Second, and far more important, it presumes that all potential votes somehow really “belong” to either Democrats or Republicans. That’s simply wrong and it does a real disservice to American politics.

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The GOP theory is that Libertarians – who often bill themselves as fiscally conservative and socially liberal – ultimately care more about spending and taxes than about, say, marriage equality, access to abortion, or drug legalization (all of which Sarvis supported). Because Republicans talk a good game on cutting the size and scope of government (whether they govern that way is a very different question), votes “wasted” on Libertarian candidates who won’t win anyway should really go to GOP candidates regardless of their views on social issues.

Democrats trot out a variation of the same argument, too, usually training their ire toward left-of-center third parties. Don’t you know that Green Party candidate Ralph Nader “cost” Al Gore the 2000 presidential election by draining away precious votes from the vice president? Indeed, in both 2000 and 2004, even the ardently left-wing magazine The Nation implored Nader not to run specifically because he might let George Bush triumph.

Since it now looks as though Sarvis actually kept the race closer for Cucinelli, it’s well past time to re-examine the whole notion that third-party candidates somehow only get in the way of serious choices that always come down to the Democrat and the Republican in any given race. That sort of thinking helps justify draconian restrictions on ballot access for minor party candidates in every state in the country.

Indeed, part of Sarvis’ appeal in Virginia was that he spoke out against the Old Dominion’s rules for ballot access and about being shut out of gubernatorial debates despite solid poll numbers. The same sort of thing happens elsewhere. In the battleground state of Ohio, which didn’t even allow party affiliations other than Democratic or Republican to be listed on the ballot for many years, pending legislation would set qualification standards so high that third parties would essentially be forced to run as write-in campaigns.

Americans have come to expect if not demand a wide range of increasingly diverse and personalized choices in every part of our lives, from coffee shops to clothing stores to bookstores. And yet in something as important as politics, we allow the two major parties to systematically rig the system to exclude a range of opinions extending beyond two parties that were founded before the Civil War. Is it any wonder that a record number of Americans now call themselves political independents?

Reflexively blaming third-party candidates when a Republican or Democratic candidate loses only adds insult to that injury. Despite having every advantage going in, Al Gore ended up losing in 2000 because, among other things, he wore bizarre orange makeup to one of the presidential debates and came across as an environmental zealot fundamentally at odds with modern industrial technology. Ken Cuccinelli lost because, among other things, he failed to assuage fears that he would bring back sodomy laws, alienated single women, and he had no connection with young voters.

The major parties already enjoy vast advantages in terms of money, brand recognition, ballot access, and get-out-the-vote operations. When their candidates lose elections, especially tight ones, they would do better to look at what they did wrong rather than off-loading responsibility or blame on third parties who give voters more options to express themselves.