John Key gave the wrong answer when asked on Friday whether he would have happily sent his children to a charter school.
His instant and firm "yes" when put on the spot was the natural reflex of a politician conscious that any hesitancy or obfuscation on his part would have seriously undermined the Act-instigated policy before a single such school had even got off the drawing board.
But the Prime Minister should have emphasised that charter schools will not be filling their rolls with the offspring of well-heeled residents of Parnell. He should have stressed "partnership schools" - to give them their new official and sanitised title - are being tested as an alternative in areas of significant socio-economic disadvantage, such as parts of south Auckland, where children struggle to learn and the present state school system, for all its strengths, is failing to deliver much in terms of acceptable results.
It is only by framing the political debate on those terms that National and Act will have any hope of turning around majority public opinion that remains convinced the policy - for which there is no electoral mandate - is the thin end of a big wedge that will increasingly farm out compulsory education to private interests to run for profit.
Friday's announcement laying out the terms and conditions for setting up and running partnership schools succeeded only in making the selling job even more difficult.
The education unions zeroed in on the provision in the new framework that the staffing of the new schools will permit the hiring of an unspecified number of unregistered and even unqualified teachers.
The focus of the argument has remained there ever since. Rather than driving the debate, the Government has largely been on the defensive.
The unions obviously have a vested interest in claiming that this is an attempt to drive down teacher salaries and further evidence of the profit motive being in play.
But they also raise legitimate questions about Government consistency.
In her now infamous pre-Budget announcement that sparked the unholy row over class sizes, Education Minister Hekia Parata placed a heavy emphasis on boosting teacher quality to raise pupil achievement levels and came up with the training programmes and tens of millions of dollars in funding to match.
So you need better teachers in traditional state schools, but not in partnership schools? The logic is hard to suss.
The big question is how damaging all this is to National. The answer is, not terribly. Though supportive, Parata has largely left it to John Banks as an associate education minister to extol the benefits of partnership schools. National is thus keeping some degree of separation.
The Government and its critics in the education lobby will no doubt lock horns when the necessary enabling legislation comes before Parliament.
The target date for the first partnership schools to be open for business is the start of the 2014 academic year - around 10 months before the next general election.
Unless things go horribly awry, the election campaign will come too soon for any meaningful assessment of educational success or failure.