New Zealand's main political fault line doesn't run between National and Labour, it separates the Nominal Left from the Real Left.
OPINION: Only very occasionally does this struggle within the Left produce a genuine rift between the major parties. Most of the time, and on most of the important issues, government and opposition maintain a bipartisan consensus. Were this not the case, it is doubtful whether our democratic institutions could survive the resulting earthquakes.
But even the strongest consensus will be weakened by events large enough to undermine the public's faith in its core assumptions. The Great Depression, for example, or, more recently, the global financial crisis (GFC), gave rise to widespread fears that the economic system, upon which we all depend, had been fatally compromised.
Inchoate and confused though they may be (just think of the ''Tea Party'' and ''Occupy'' movements in the United States), the popular demand that ''something must be done'' renders the consensus-based politics of more settled times untenable.
This is precisely what's been happening in New Zealand since the onset of the GFC in 2008-09.
Between 1999 and 2008 the Labour-led government of Helen Clark and the National Party opposition were able to preserve a pretty broad consensus on the big economic and social issues. The market-led policies introduced by the fourth Labour government during the 1980s and entrenched by National in the 1990s remained firmly in place. Labour made no effort to restore Jenny Shipley's swingeing benefit cuts.
Labour's loss of the 2008 general election and the departure of Helen Clark put an end to all that.
Among the party's rank-and-file and its trade union affiliates there was a growing clamour for Labour to acknowledge that the market-based policies of the past 25 years had failed and that it was time to return to the labour movement's core principles for answers to the burgeoning economic and social crises of the 21st century's second decade.
Within Labour's caucus, however, there was a profound unwillingness to step outside the quarter-century consensus it had forged with National. So long as that consensus endured it was possible for Labour MPs to go on believing that modern politics, stripped of all its distracting rhetoric, was still mostly about the orderly rotation of political elites.
For politicians like Phil Goff and David Shearer, the job of a Labour leader was simply to assemble a credible alternative government: a group of competent, professional politicians ready to take over the efficient running of the country when the incumbents, exhausted by the demands of office, were no longer able to muster the required level of electoral support.
Theirs was a purely nominal leftism: rhetorical, formulaic and reliant on a faded symbolism which very few professional Labour politicians any longer took seriously.
Like Helen Clark before them, Mr Goff and Mr Shearer and their nominal leftist colleagues were alarmed by the party's insistence on infusing Labour's message with genuine Left-wing ideas. The last time the party had done that was under the leadership of Norman Kirk - and that had not ended well.
People often wonder why David Cunliffe is so disliked by so many of his colleagues. The answer lies in Mr Cunliffe's realisation that the GFC and its aftermath requires a comprehensive rethink of Labour's entire approach to contemporary politics.
It's a position that obliges Labour MPs to become genuine leftists. It's why Mr Cunliffe's colleagues have gone to such lengths to prevent him becoming the leader of the Labour Party. It also explains the rank-and-file's steely determination to change the rules governing the leader's election.
Labour's ''primary'' election is, therefore, much more than a contest between three Labour MPs for leadership of the party. This is political tectonics: the slow buildup and sudden release of massive and competing political energies.
Either Mr Cunliffe and the irresistible forces of Labour's Real Left will be lifted up to victory and radical change. Or, he and his followers will be driven down deep by the Nominal Left's immovable objects.
- The Dominion Post