The one-seat threshold survives simply because it could yet be the difference between National staying in power and going into Opposition. But that does not make it right.
Instead of feeling chastened by its cheating voters of a change in the rules, National will most likely reach "electoral accommodations" not only in Epsom, where it has let Act take the seat in the two past elections, but also in two other electorates.
In Wellington's Ohariu, National will want to avoid splitting the vote for Peter Dunne and stop the Labour candidate coming through the middle.
Similarly, National is likely to gift East Coast Bays to Colin Craig, should his Conservative Party still be polling at only 2 to 3 per cent, to ensure votes for his party are not wasted ones.
However, it seems to have dawned on the Prime Minister just how manipulative all this is beginning to look.
The word "gerrymander"- one not usually associated with New Zealand's voting system - surfaced in questions at Key's weekly news conference on Monday.
In response, Key chose his words very carefully as he parried further questions about the likelihood and timing of accommodations.
While he wanted to be "transparent" about such deals, he was reserving the right to hold off announcing them possibly until as late as the early stages of the official election campaign.
The Prime Minister's remarks suggest he realises that National has become too blase in turning parliamentary seats into playthings akin to the "rotten boroughs" of old England and a return to more careful political management is in order.
A 3 News-Reid Research poll this week confirmed something which had long been suspected.
Voters do not like such deals where a major party urges its supporters, either by way of a coded statement, a symbolic get-together, an outright declaration or even withdrawal of its candidate, to cast their electorate vote for a minor party ally in order to engineer a parliamentary majority.
Close to 70 per cent of would-be Labour voters were opposed in principle to such deals. The rejection rate was even higher among supporters of the Greens and New Zealand First.
Perhaps most surprisingly and most significantly, some 35 per cent of National supporters also opposed the practice.
Those people along with the wider public are justified in feeling they have been cheated.
They were promised a review of MMP if it survived the 2011 referendum on it continuing to be New Zealand's electoral system. It did survive. The review was conducted by eminent Electoral Commission figures of unimpeachable character who had no axes to grind.
Among other things, they recommended abolition of the one-electorate threshold, saying it unfairly gave voters in some electorates "significantly more influence" in determining the make-up of Parliament.
The German MMP system's equivalent of the one-seat threshold was introduced to ensure ethnic minorities concentrated in specific parts of the country had a voice in the Bundestag.
In the New Zealand context, the purpose of the one-seat threshold was never obvious. It is now seen by members of the royal commission which recommended MMP to have been a mistake.
The Electoral Commission also recommended the provision for "overhang" seats should be axed and Parliament be kept to a maximum of 120 seats.
This change would have rendered it pointless for National to let Act or other minor parties each secure even a lone seat as those would probably be cancelled out by National losing MPs to make room for them.
National's response to those recommendations, which had wide support from those making submissions to the review, was cunning but also predictably self-serving.
Justice Minister Judith Collins loftily announced there would be no changes as the convention that there be an all-party consensus for measures altering aspects of the electoral system was lacking.
This seemingly principled stance played on public ignorance by conveniently neglecting to mention it was National and Act which were blocking such a consensus.
At least Act's new leadership has accepted that relying on National not fighting in Epsom is not a viable strategy for guaranteeing Act's parliamentary survival long-term.
Even so, National and Act are certain to test the patience of Epsom voters for a third consecutive time at the forthcoming election to ensure Act's new candidate, David Seymour, gets into Parliament as insurance should National need the slight mathematical advantage his presence would bring in increasing the odds of National remaining the governing party.
To his immense credit, Act's new leader, Jamie Whyte, has flagged his resignation should he fail to make hay from the accommodation - which will guarantee a party vote for Act is not a wasted vote - to lift Act's total party vote to a level which would see him join Seymour in the House.
It may be a long shot, but giving Whyte time and breathing space to try to raise Act's poll rating to, say, 1 or 2 per cent, is probably one reason - along with the public antipathy towards accommodations - why Key is suddenly not being definitive about them.
He will also be conscious of the danger of National being associated too closely with the likes of Craig's Conservatives and their capacity to cause political embarrassment.
No one knows better than Key that giving voters a nod and wink as to how they should tick the ballot can come badly unstuck - as in the case of the Epsom "cup of tea" with John Banks which partially derailed National's election campaign in 2011.
Using such exercises as symbolic means of communicating how people should vote had some value when voters had to be gently prodded to tick for the first time the name of someone not from their favoured party.
Now that voters are far more conscious of what might be required of them, Key's desire to be more direct and transparent is the right call.
That is not sufficient excuse, however, to remove the stench of something rotten in the state of New Zealand's democracy.
Debate on this article is now closed.
