Until now, it has been assumed Labour has managed the political relationships with other parties under MMP far better than National.
Three years ago, Don Brash completely misunderstood MMP, running National's campaign under a two-party electoral mentality. Despite Act pleading to be their ally, National tried to destroy them. It also went out of its way to launch a red-meat attack on Winston Peters in Tauranga. To reinforce its stupidity, its Maori-bashing hysteria ensured it alienated the Maori Party, too.
Brash lost to Labour by only one MP, yet Helen Clark was able to form a third-term government with, essentially, a 20-seat buffer. To its right, Labour had NZ First and United Future, and, on the left, Jim Anderton's Progressive Party, the Greens and the Maori Party.
Clark had worked out years before that she could keep coalition options open by maintaining polite and collegial relationships with all minor parties. In this happy situation, Labour would be the permanent government under MMP.
However, the ultimatum by Winston Peters and Peter Dunne - that they would not support a Labour-led government if the Greens were in it - set up the situation where Labour's hegemony of the minor parties would ultimately fracture.
At the last election, the Green Party had positioned itself, like the Alliance before it, so the only electoral deal it could do would be with Labour. This effectively made it impotent in any coalition negotiations.
Once Clark had dismissed the Maori Party as the "last cab off the rank", the Greens were screwed. Labour went for the short-term, expedient deal, which, at the time, seemed a master stroke. It kept the Cabinet and, by offering Peters and Dunne ministerial portfolios outside Cabinet, had a comfortable parliamentary majority. The Greens had no choice but to take a few crumbs as a consolation prize.
At the time, Greens co-leader Rod Donald was devastated at what he thought was a betrayal by Labour. The current leadership, after Donald's untimely death shortly after the election, understood clearly that they would not be put in the position of Labour's footstool again.
This term, Green Party MPs have resented the disdain and disrespect with which Labour ministers have treated them. At their conference last week, co-leader Russel Norman laid out the Greens' more aggressive, independent position on coalition matters. On working with either Labour or National, the Greens have formally adopted the same policy as the Maori Party. Norman's attack on Labour and National as tweedle-dee and tweedle-dum is the first salvo in this election.
Under normal circumstances, I would argue this is mere electoral posturing, given that several Green MPs, including Norman, have socialist-left backgrounds. But it is clear their mood is to move to a more centrist and pragmatic electoral position. With Labour now so far behind National in the polls, they won't get enough MPs in Parliament to keep the government jobs even if all the minor parties back them.
United Future and NZ First have positioned themselves to work with either of the two big parties. Jim Anderton and Rodney Hide effectively cancel each other out in the electoral math, because the Progressives are fused at the hip with Labour, as is Act with National.
The Greens felt betrayed last time and won't put themselves at Clark's mercy again. But ultimately the Green Party probably has no choice but to align with Labour, given that its supporters are on the centre-left of the political spectrum. What's more - and without being unkind - I don't think the National Party would have a bar of them. Even with John Key's promotion of a softer National Party, it's safe to say the Green Party is National's "last cab off the rank".
The Maori Party is a real potential for Key if National can't gain enough support from Act and United Future, and assuming NZ First doesn't make it back. The Maori Party is Labour's competitor in the Maori seats and National has decided not to run candidates there. Last time Labour ran a somewhat successful strategy against the Maori Party by saying that a vote for the Maori Party was a vote for National. Given that the Greens, United Future and NZ First take a similar position, this won't have the same impact as last time.
So we are in an ironic position where Labour needs loyal electoral allies. The Maori and the Green parties, which Labour will need to survive, are hedging their bets.
Labour's decision to do a deal with NZ First and United Future has come back to haunt them. Neither is politically viable and won't survive when their leaders retire. The Green and Maori parties, which will survive long term, were alienated and are now taking their revenge.
On election night, Clark may well find herself in the same position as National three years ago. Key will have many coalition options and Clark none. The irony is that her political isolation will have been self-inflicted.