One of the great pseudo-hardboiled statements you can make about American politics is to shake your head with resignation and sigh that the major party candidates are no different than Coke and Pepsi.

But while the underlying assumption – that people can only be tricked into passionately supporting one or the other indistinguishable party through constant marketing and advertising – may be correct, the truth is that we'd be much better off, and enjoy much greater diversity of political representation, if America's politics were more like its cola markets.

A breakdown [pdf] of soft drink brand names shows that neither Coke nor Pepsi has the kind of iron grip on public attention that the two factions of the political duopoly have exercised for at least as long as every American voter today has been alive.

Even robust third-party challenges like John Anderson's in 1980 (6.6 percent of the popular vote) and Ross Perot's in 1992 (an astonishing 18.9 percent of the popular vote) have never brought the Republocrats' share below one-third each. The graphic above is from 2001, when the internet was still black and white, but a 2010 report shows continued diversity:

It is true that in the last ten years the Coca Cola Company has taken a decisive lead in the soft drink wars, with all its combined brands now holding 42 percent of the market to PepsiCo's 29 percent. (And it goes without saying that we don't have any subsidiary choices like Democrat Zero or Republican Free.) That still leaves a level of diversity in third-tier brands that you rarely see in politics and never in presidential elections.

If Barack Obama and Mitt Romney were truly Coke and Pepsi, Libertarian candidate Gary Johnson, the standardbearer for the country's third largest party, would be polling above 10 percent right now. In fact, he is polling around 3 percent – which is an excellent showing by historical standards. In 2008 Libertarian candidate Bob Barr brought in just 0.4 percent, behind Ralph Nader's 0.56 percent, and all minor-party votes combined came to less than 2 percent. If you've been following Garrett Quinn's coverage of Johnson's ballot-access Iliad, you know these low percentages reflect intentional choice-reduction tactics by the major parties more than they do the will of the voters.

Am I saying that the soft drink market is perfect? I am not. In my view more people should appreciate the reliable taste and reasonable price of Shasta, and I tremble for my nation when I reflect that we have such little regard for RC Cola, which has great taste and made the best cola commercial of all time back in the 1980s:

Those were bolder days, when America had a real president who knew that you respond to an attack on your embassy by selling arms to the attackers. But even today, some sharp marketing executive could easily persuade hipsters that "Royal Crown and Crown Royal" is a swanky successor to your father's rum and Coke. I'd doubt that kind of ingenuity would make a difference in our choiceless politics.