Heather du Plessis-Allan: Why the Green Party will be gone in a decade

It's never wise to make bold predictions in politics, but here's one I'm willing to make.

Unless something major changes within the Green Party, it won't be in Parliament in a decade. In fact, a decade may be too generous.

I say this because the Green Party has a split personality. The co-leadership battle has shown us how bad it is.

If you assumed the co-leadership contest between Julie Anne Genter and Marama Davidson was simply about two women interviewing for a job, you'd be wrong. It was so much more than that.

These women are the yin and yang of the Greens.

Genter is the kind of person you'd expect to find in a party called the Greens. She wants to save the planet, is obsessed with public transport and probably eats organic food.

Davidson is a whole different kettle of fish. She's the darling of the far-left social justice warriors, her fans are the same people who loved it when Metiria Turei openly admitted beneficiary fraud and you get the feeling the environment isn't Davidson's top priority.

This leadership battle was really a death match over which is more important to the Greens: the environment or beneficiaries.

And the fight got heated. This week a group of Young Greens threatened to quit the party if Genter won. Given the party's future direction is at stake, each of these women has a passionate fan club inside the Greens. And while the fans adore their own poster child, they don't feel nearly the same level of adoration for the other.

You know how passionate English football fans can be about their own club? And how much they despise any opposing team? It's a bit like that.

This is why the Greens won't last 10 years unless they make big changes. The split personality can't go on living together. Not only is the animosity in the party too great, but not all voters who care about the environment also want to give hand outs to beneficiaries.

Take, for example, Jenny from Pukekohe. She hasn't bought plastic food wrap since she learned turtles choke to death on the stuff, goes to great lengths to recycle and wants to leave a clean planet for her grandkids.

But she also worked hard to pay off her mortgage so doesn't like the Greens' policy to introduce a 40 per cent tax on income over $150,000 or their policy to increase the dole by 20 per cent.

Jenny and her mates will be the first to desert the Greens when another party gives them an alternative place for their votes.

They won't have to wait too long. Caring for the environment is no longer hippy politics. Every party is starting to do it. Virtually the first thing Labour did in Government was to ban plastic microbeads. NZ First has a policy on carbon pricing. Act wants to cut emissions.

Oddly enough the biggest threat is coming from the party the Greens are mostly likely to hiss at: National.

There's a long tradition of Blue-Greenness within the Nats and things are really starting to ramp up. In his first interviews in the job, new leader Simon Bridges couldn't have made it clearer he plans to go greener.

Once all the other parties go green, the Greens will lose their big point of difference. And what are they when that's gone?

All they'll be is a far-left party that condones beneficiary fraud and wants to make it easier to stay on the dole.

We saw how that went down for Turei.

I don't rate the Greens' chances.

• Heather du Plessis-Allan is on NewstalkZB Wellington, weekday mornings.