As long as that provision remains on the statute books, there is a chance - however slim - that Act leader John Banks and United Future leader Peter Dunne could bring one or two extra MPs into Parliament at the next election, thereby upping the chances of the centre-right remaining in power.
Speaking the day after the commission's final report on the future of MMP was tabled in Parliament, the Prime Minister yesterday pretty much flagged that the one-seat threshold would remain.
It was important, he said, that governments contemplating changes to the voting system were seen to be fair and even-handed. Translation: ditching the one-seat threshold would not be fair on Act and United Future.
It was important there was a consensus in Parliament for passing new legislation. Translation: there is insufficient consensus.
It was normal for a Government to accept some recommendations made by an organisation like the Electoral Commission. Translation: we will reject recommendations we don't like.
The commission was "just another body" which "looked at things" and took a perspective which it thought was right. Translation: what the Electoral Commission thinks is not that important and governments can get away with ignoring what it has to say.
National should not get all the credit for being so self-serving. Labour's support for dumping the one-seat threshold has to be put into context. None of its allies rely on that provision to get their MPs into Parliament.
That makes Labour's drafting of a bill to enact the commission's recommendations exactly on a par with what National is doing - playing politics with a matter which should be above politics.