I am almost feeling sorry for the Greens. The self-proclaimed party of principle has struggled with the reality of Government, ever since it joined the unholy alliance with Labour and New Zealand First last October. They are the awkward members at the family dinner-party - the guest Labour really wanted to be in the box seat, but the one New Zealand First wanted left at home altogether. So the ungainly compromise was reached, where the Greens can join the feast, but have to eat in the kitchen, and not the dining room where Labour and New Zealand First recline.

And, if that is not bad enough, they have to go along with whatever is agreed in the dining room, before they get any food at all. They have had to do an about-face on their hitherto principled opposition to party-hopping legislation. Allegedly, according to the rumour mill, this was because of a threat from New Zealand First to release more damaging material about the background circumstances of Meteria Turei's benefit abuse hara kiri last year. Whatever, the claims to be the party of principle have been left looking more than a little tatty.

On the positive side, though, the Greens appear to have made progress on their aim of moving the economy to a carbon neutral status, although their proposals are at only discussion paper stage at present, and could yet be derailed by New Zealand First, or even Labour, if the going gets tough from here on.

Moreover, the Greens' position has been made more difficult by the electoral mathematics. Labour cannot govern now or in the future without the support of both New Zealand First and the Greens. If the Greens were to walk away now, the Government would fall, and they would be punished at the ensuing election. On the other hand, there is no guarantee that one or other, or even both, New Zealand First and the Greens will make it back at the next election, so the Government could fall anyway.

In many senses, the Greens are in no different a position to every other support party over the years. Having made the decision to support a major party in Government, they are virtually duty bound to see the term through. Yet the consequence might be their defeat in the long term, although if they were revert to being the party if principle and leave sooner, they would assuredly be tossed out of Parliament. Successive support partners over the years have faced the same dilemma, and have been derided by the Greens for being without principle when they have stayed the distance. So there is rich irony in the Greens' present plight.

What has complicated the Greens' position further is that they boxed themselves into a corner. They made it clear they would countenance working with Labour only, and, for reasons which are understandable if politically inflexible, ruled out working with National under any circumstances. So desperate were they to be finally part of Government, after having being shut out at every election since they left the Alliance in the late 1990s, they even failed to do basic due diligence on the Labour/New Zealand First coalition agreement, before signing up, sight unseen. Now they are left to reap the whirlwind.

Moreover, to make matters worse, they are facing internal party wrath over their Conservation Minister's decision to expand a water bottling operation, one more thing they railed so strongly against in Opposition. For the record, the Minister made the correct decision, given the legislation, but, as with so many other things this Government does, conveyed the decision so poorly the party backlash was inevitable.

It has to be acknowledged that individually the Green Ministers are very talented, certainly in comparison to their New Zealand First counterparts, and most of Labour as well, but they are simply not functioning well. Nor are things likely to improve as the going gets tougher over the next two years. The Green Ministers add to the competence of the Government, but that may not be enough to save them, either from themselves or the wider electorate.

Maybe it is time for the Greens to rediscover their Green-ness. Maybe it is time to make it clear that while they will continue to support the government on matters of confidence and supply, so that stability is not threatened, they will approach every other issue on the basis of how it impacts upon their Green agenda. With confidence and supply assured, neither Labour nor New Zealand First, could credibly claim that the Government's stability is threatened, so any retribution against the Greens would be of their making, and not the fault of the Greens.

It is a difficult balancing act. In the last Parliament, both the Maori Party and UnitedFuture played such a role, and were defeated. ACT was a more uncritical supporter of the Government, but equally derived no electoral benefit.  Just as the Greens see being part of this Government as critical to their ability to make policy change - and they are right, they know full well parties can do nothing from Opposition - they have to also see that for their changes to have any meaningful impact, they have to get re-elected in 2020. After the initial flush of at last getting into Government, the more mundane reality of how to stay there should be starting to hit home. So far, there is no real sign it is.