It was bad news enough for Labour this week that two major opinion polls registered morale-sapping widening of the gulf in the party's support compared with National's rating - a gap which had begun to close in previous months.
What had Labour seething, however, was the errant wording of a question in the 3News Reid Research poll.
The mistake may have been an oversight rather than an attempt to skew the result. But Labour felt it was at best the victim of sloppiness and at worst the target of a media stitch-up.
The survey asked voters whom they trusted when it came to managing the economy - John Key and Bill English, or David Shearer and Russel Norman.
That Mr Key and Mr English were preferred by 55% to 37% came as no great surprise to Labour, being similar to the result of the party's own polling.
What really annoyed Labour was the inclusion in the poll's question of Mr Norman, the Greens' co-leader, instead of David Parker, Labour's finance spokesman.
Labour will make Mr Parker's appointment as Minister of Finance an effective bottom-line in any post-election talks with the Greens.
Mr Norman makes little secret of his wish to hold the plum job. For all his efforts to talk the lingo of the economic mainstream and demystify Green economics, he will not get it.
Labour will not relinquish control of that most powerful of portfolios for three reasons: first, to maintain control of the coalition and maintain its stability by having the prime minister and finance minister from the same party; second, to avoid panicking the many voters who are yet to be convinced Greens are not ''whacko'', as Mr Key puts it; and, third, the Greens are unlikely to hold enough seats to force the issue.
However, something else may frustrate Mr Norman's and other Green MPs' ambitions and no doubt it will get some airing at the Greens' annual conference in Christchurch this weekend, though it will be difficult to know because the party which claims to be passionate about the concept of open government has shut the media out of most sessions.
It has long been assumed that should the next election deliver the requisite number of seats, Labour and the Greens would bury their differences and form a centre-left government.
That would still seem likely, but it is by no means guaranteed.
Mr Shearer is increasingly making references to a ''Labour-led'' government, not a ''Labour-Greens'' one. This is in part to counter Mr Key's demonising of such a combo as the ''devil beast'' by making it clear Labour will very much be in charge.
But it is becoming clear that Labour thinks it might be preferable to strike a deal with Winston Peters.
There is a growing belief it might be easier to govern with New Zealand First than the Greens, who can be fractious, averse to compromise and prone to being holier than thou, and are in fierce competition with Labour for the same segments of the vote.
There are strong indications Mr Peters is less inclined to be party to a Labour-led government which includes the Greens.
If Mr Peters held the balance of power, he might well eschew a three-way arrangement with Labour and the Greens and align with National.
It would thus be in Labour's self-interest to ignore the Greens and negotiate with Mr Peters.
The immediate difficulty with that is Labour and NZ First combined would be unlikely to secure a majority in Parliament. However, the Greens might find little choice but to prop up a Labour-NZ First Administration, if only through abstention. The Greens would have nowhere to go, having made it pretty plain that they and the current ruling party are fundamentally incompatible. The problem with hypothesising is that - apart from the risk that things could get really messy - Labour cannot be guaranteed NZ First MPs will be returned to Parliament in 2014 in sufficient number, if at all.
The Greens will definitely be back - and in number. And Labour may be left with no choice but to work with them.
The two parties have an odd relationship. Labour and the Greens are forever trying to escape from one another but are doomed to having to live together. It is a relationship which has the life and energy sucked out of it by an underlying and debilitating mixture of ambivalence and wariness towards one another.
The respective leaderships meet fairly regularly, but there seems to be little enthusiasm when it comes to projecting a government-in-waiting.
The closest thing to that happening was the joint press conference in April which saw Mr Shearer, Mr Parker and Mr Norman share a platform to unveil their broadly similar plans to intervene in the wholesale electricity market to force down power prices.
The joint release of policy happened by accident, not design, however.
Labour is not keen on a repeat. That reluctance is based on the assumption by Labour that the Greens got more positives out of the exercise than Labour did.
As the larger partner in the relationship, Labour accepts - but also resents - that it must play the responsible role, while the Greens can peck away at Labour's base support by making promises they know they will not have to keep.
Meanwhile, the communication vacuum has been filled by Mr Key and Steven Joyce with their denunciations of the Greens as anti-economic development and Labour likewise guilty by association.
There are two schools of thought within the two Opposition parties regarding National's attacks. The first says it is better to ignore the vitriol on the basis that line of attack will have been exhausted by the time next year's election campaign rolls around.
The second argues that it is a mistake to allow Mr Key free rein to ''frame'' Labour and the Greens in an image which becomes harder and harder for those two parties to wipe off.
This weekend the Greens will try to render null and void Mr Key's potent line that next year's election will be fought between ''the centre-right and far left'' by claiming he is the extremist, not them. It is a claim that is unlikely to wash, however.
- John Armstrong is The New Zealand Herald political correspondent.
