You have to credit the Labour Party for breathing new life into discredited ideas.
In this case, inadvertently rousing the ire of the anti-vaccination lobby by suggesting unvaccinated children shouldn't be allowed to attend daycare.
Andrew Little frothed at the mouth, went red in the face and said it was "well worth looking at", which for the timorous party he leads is positively table-thumping.
The anti-vaxxers went off.
I thought we'd seen the last of the debate about vaccinating children, just as I thought we'd seen the last of measles, mumps, whooping cough and smallpox - all diseases
Time magazine reported in 2014 were making a comeback.
I know - mainstream media, right? There they go again with their facts.
The magazine credited the comeback of the diseases to the refusal of some parents to have their children vaccinated.
When my children were barely able to walk it was a great pleasure to be able to look at them in the knowledge they wouldn't get, for instance, polio, the last sufferers of which were still a visible presence in the community when I was growing up.
This is an issue for which, by the way, there is no question in the mind of 2014 New Zealander of the Year Lance O'Sullivan, the mildly messianic GP who actually has to work with the consequences of unvaccinated children in the Far North.
He came out in favour of compulsory vaccination - no ifs, ands or buts - in 2014.
But a preschool ban puts the emphasis in the wrong place. It should not be on keeping unvaccinated kids home, but on getting them to the doctor to have their shots.
The idea of compulsory vaccination is offensive to many because they see it as an issue of freedom of choice. For them, this is the heavy hand of the nanny state.
I've never understood why "nanny state" is seen as a pejorative description. Nannies are kind, warm, smell good and in extreme cases use their umbrellas to fly.
And children, it's worth remembering, don't have freedom of choice. They depend on others to make the right choices for them.
And besides, we are compelled to do many things we might not otherwise bother to, but few of them save lives, reduce healthcare costs and generally make the world a better place to the extent that vaccination does.
We wear seatbelts, for instance, in most cases because we know this is a sensible precaution but also because the law tells us to in order to ensure our own safety. We have to maintain our cars to a reasonable standard of safety so they will not be a danger to others.
But these arguments hold no sway with the anti-vaccination sceptics, many of whom come across as though they would consider bubonic plague to be merely an alternative lifestyle choice.
Calling them sceptics is unfair to sceptics, who base their conclusions on evidence and reason. Many have bought into the totally discredited theories of Andrew Wakefield, who linked the MMR vaccine to autism in a 1998 paper in The Lancet. The paper was as scientifically robust as The X-Files. It was subsequently withdrawn and he was struck off.
Now he has made a movie that sings his looney tune - Vaxxed - whose promoters are so worried about protests that screenings are being advertised by text three hours before.
Despite isolated exceptions - such as that of Wakefield - doctors aren't as a rule in the business of exposing people, particularly babies and children, to life-threatening procedures.
The most threatening procedure in this whole argument is leaving children unnecessarily exposed to disease.