Once it was a colour combination frowned upon in the world of fashion (or so I am told). But apparently haute couture has moved on. Should our politicians do so too? 

Watching Bill English and James Shaw respond to questions this week on the possibility of a National/Greens coalition, it is plain neither is comfortable with the concept.

Yet if our political parties – of whatever colour – were true to the MMP game, they would put old loyalties aside. Traditional alliances reflect monochromatic, FPP thinking, when MMP elections come in technicolor.

Our lack of MMP imagination comes with a high price. It restricts the choices of the major parties, and rules out more interesting policy options. Just read Oliver Hartwich’s column in today’s NBR to see how this has played out in his native Germany, the home of MMP (see here).

It is hardly as if environmental issues sit on a left/right political spectrum. They occupy a different dimension. This is why in Germany, after their election on Sunday, a coalition between their equivalents of National, the Greens and ACT appears the most likely outcome.

So how might a Blue/Green coalition work? Well, the two parties have more in common than they might think.

Philosophically, there is nothing more conservative than caring for the environment. And economically, a clean environment is a must-have for New Zealand. New Zealand’s tourism brand depends on it – as does the reputation of our agricultural sector.

National should have no problem cooperating with the Greens position that our environment deserves more attention. Indeed, it is accepted across the political divide that our waterways need cleaning up. A National/Greens government could achieve this with an innovative regime for tradable water trading, a concept that would also solve the water allocation problem ignored by Labour’s proposed tax.

New Zealand also need much smarter transport policy, including road pricing. This is fertile territory for a Blue/Green solution.

And much of what we have tried in justice policy has not been working. A Greens Minister of Justice could have a mandate to reform New Zealand’s drug policy, and to introduce new ways of tackling recidivism.

This election is the Greens’ best chance to be in government since they were formed. They cannot do much outside the coalition or in opposition. And they would struggle to achieve the same kind of meaningful change with NZ First in any case.

If traditionalists in the fashion world can break down old barriers, maybe our politicians should too.