Telegraph blogger Tom Chivers has no qualms that ‘the three “mainstream” parties… are all essentially the same.’ As he writes, ‘The mainstream parties have worked out that if you want to win a respectable number of votes, you have to be pro-market while at the same time not anti-gay.’ Is he unconsciously channelling public choice economics which argues that good politics will echo the voluntary nature of the free market?

For as Gordon Tullock observes in The Vote Motive, ‘The market operates by providing a structure in which individuals who simply want to make money end up by producing motor-cars that people want. Similarly, democracy operates so that politicians who simply want to hold public office end up by doing things the people want.’

Chivers accounts for this lack of political diversity as the outcome of a dialectical process. ‘We had our great back-and-forth between huge radical ideas. It’s still going on, but the outer boundaries have been, by and large, delineated. Marx would probably have called it thesis, antithesis, synthesis.’ Public choice economists would call the process by another name. In Government: Whose Obedient Servant?, Tullock describes this as ‘the median voter theorem’:

‘Assuming that the candidates of two [or more] parties are intent on winning the election, and assuming that voters will vote for that candidate who most closely approximates their own preferred political position, politicians will not choose political positions out on the wings of the distribution. A candidate who takes a political position on the wings of the voter distribution can be beaten at the polls by a candidate who moves into the middle of the distribution of preferences.’

And what of those fringe parties out on the wings? ‘There are more radical parties available,’ notes Chivers.

‘And it’s not as if they get ignored, that they’re squeezed out of the electoral picture by the ruthless machine politics of the big parties: Ukip and, to a lesser extent, the Greens have demonstrated that it’s possible to get a significant following with radical policies. There are places to go, if you think the mainstream parties are too mainstream. Go and vote Socialist Workers Party. Go and vote BNP. Some people do. But – and this is the great thing – not very many.’

But, as public choice reveals, the fringe can win elections – but usually if it is embedded within a mainstream organisation. Tullock illustrates graphically in The Vote Motive (see p. 57) how polarising party wings can give a party an advantage over opponents which share similar policy programmes. ‘In a two-party system there is a simple operational rule for the politician,’ he writes: ‘find out what the other party is doing and take a position very close to it in the popular direction. With a three-party system, nothing so simple exists.’ A party which moves away from the middle may lose votes in the centre of the distribution, but pick up votes around the edge, resulting in a net gain.

This scenario is arguably unfolding in the United States, courtesy of the Tea Party phenomenon. Named for the American patriots who dumped tea chests into Boston Harbor to protest tariffs and proclaim ‘no taxation without representation’, the activist movement arose in 2009 in defence of constitutional limited government, under assault by Wall Street bailouts and crony capitalism in Washington. To borrow Chivers’s analysis, the Tea Party is engineering a dialectic within the Republican Party which will serve to strengthen its conservative principles (not moderate them, as can be surmised from a conventional dialectical exercise). According to a New York Sun editorial,

‘…in the rift that is rending the Republican Party, the Sun is on the side of George Washington.

We speak of him as the personification of the constitutional founders. Few of our political loyalties are personal. Our base is the Constitution, at the drafting of which Washington presided. […]

If the Tea Party succeeds, it will be because it is looking beyond the moment to America’s founding principles.’

And, unlike the fringe parties which do not have elected members in Westminster (although they do have sitting peers in the House of Lords), a Tea Party caucus sits in both the House of Representatives and Senate, with such influential GOP politicians as Marco Rubio, Ted Cruz and Rand Paul.

Chivers’s conclusion is that ‘the mainstream parties are moderate because the British people are, by and large, moderate. Forgive me if I can’t see that as a terrible state of affairs.’ But for the electorate who prefers substance at the expense of consensus, a public choice model can give them – unlike the dialectical model, for instance – principled politics. Republicans in America can thank the Tea Party for stiffening its constitutional backbone; will a ginger group emerge among the Conservatives to give them a cause beyond power and winning Number 10?