A look at how we got into this legal highs muddle and how the government's knee-jerk reaction is all about the drug of power rather than any evidence on legal highs themselves

We all know that drugs have mid-altering qualities and can do odd things to your brain, but who would have thought that legal highs were so powerful that they could alter the minds of nearly every MP in New Zealand so suddenly.

Less than a year ago MPs voted 119-1 in favour of the Psychoactive Substances Act, creating a regulated market for approved synthetic drugs. (The only vote against was from John Banks, who didn't oppose a regulated market approach, but merely the fact the new drugs could be tested on animals). It was a controversial move for parliament to endorse a legal drug market in New Zealand; previously the drugs had been legal, but only because they were new creations that got around existing laws.

For more than a century, our politicians have maintained a prohibition on mind-altering substances (alcohol being the obvious exception) as a way of expressing social disapproval and protecting people from themselves. New Zealanders have tended to respond by not taking those laws terribly seriously; a large proportion of New Zealanders have used marijuana, for example, by internaitonal standards. Yet at the same time there has been no public appetite for decriminalisation, so politicians have maintained the bans.

Then, last year, they took a new approach. New chemical compounds not covered by any laws were being used widely and attempts to ban the products were not stopping their use. Every time the government added a product to the banned list, a new one was invented by the legal high chemists. What's more, the MPs accepted the argument that to ban legal highs was to simply drive customers from legal retailers to the black market.

They decided to try something different.

But they butchered the process along the way. The new law banned almost all the legal highs available, leaving for sale just the 41 considered to carry the lowest risk. The Ministry of Health was to devise a testing regime which determined an acceptable safety threshold for any new drugs created. That regime was slated to be introduced in early-mid 2015. Long story short, that was far too long to expect the public to wait and pressure has built to the point where the government was caught on the wrong side of strong public opinion. Just five months from an election, that couldn't stand.

So Associate Health Minister – our own legal highs tsar – Peter Dunne acknowledged this weekend on The Nation that he'd got the law wrong. He said the new law should have pulled all the products and only allowed them back on when the testing regime was in place and they were shown to be low risk. He was going to bring the testing regime forward; rather than being introduced next year he wanted it done inside three months, he said.

Yesterday, with Labour about to announce the same policy today, he declared all legal highs would be pulled from the shelves as soon as parliament could pass an amendment to his bill under urgency, in two weeks time.

That's how we got here. But where in fact are we? In an utter muddle, frankly. This policy switch undermines every argument that's been made for the past year and shows a government now trying to do what it has previously said is impossible.

The most generous interpretation is that at least politicians are listening to voters and responding to the popular will. Closer to the truth, however, is that public panic (based on dubious information) has forced politicians in an election year to buckle and a u-turn with no evidence to justify it.

Let's look at the contradictions in all this. The principle in the law is that New Zealand is not banning legal highs because bans don't reduce demand or make people safer. Yet every decision since by the government has encouraged one sort of de facto ban or another.

First, councils were empowered to say where legal high shops could open for business. Well, more than that – the government said there would be no more licences granted for new legal high shops. So only those retailers with a licence already could sell the products. Then, councils were told they could pull the licences of those shops too close to sensitive community spots.

As public opposition to legal highs grew louder, councillors were the first ones to hear and understand the degree of public outrage. So naturally they looked to use those geographic restrictions as a de facto ban. Hastings had two legal high shops – one was decreed too close to a church (within 100 metres of a sensitive site), the other too close to the first one, as mayor Lawrence Yule explained on The Nation. Both were closed down and Napier (presumably not as good at finding places to label as "sensitive") was stuck with the only shops in the region. Cue the queues and anger in Napier.

Hamilton also acted quickly, naming sensitive sites that included bus stops, public toilets and even the Waikato River. Coincidentally, all the city's legal high shops were within 100m of the named sensitive sites and all were forced to close.

The legal highs lobbyist The Star Trust saw the writing on the wall. Calling it "old school prohibition" it took Hamilton City Council to court; the case is still pending, in July.

So even before this weekend we had a law that rejected a ban, yet local councils doing all they could to enforce one. And the government backing them in their de facto bans.

Yet Dunne still made the argument that bans don't work, for two reasons: First, that manufacturers could alter any substance by a molecule and get around any list of banned substances. Second, that it would drive buyers away from legal sellers to illegal ones.

He even said on The Nation that he'd spoken to the Irish Health Minister in the past month, who had told him that the ban imposed there in 2010 had been a "disaster". The demand for the drugs was undiminished, but the sellers were now illegal blackmarketeers rather than licensed shops. Dunne said his Irish counterpart wished they'd never imposed the ban.

Yet here we are – just a couple of days later – with licensed retailers in New Zealand now being stopped from selling the products. Ahem – a ban. Using Dunne's own logic, the demand for the drugs won't diminish and sales will simply be made by those willing to break the law. And probably charge a higher price in the process.

The change in approach has everything to do with public opinion and nothing to do with evidence. Because here's the key question, the only question that really matters today: Has the use of legal highs changed since the law was passed last year?

If it has, then there's every reason to say we should learn from experience and change the law. If harm is increasing, then maybe it's wise to try something different.

So where's the evidence for that? As far as I know, there is none.

The only point that you might make – and it's only anecdotal – is that some marijuana users seem to be moving to legal highs because they're easier to get, cheaper and you can't get drug-tested for them at work. So some existing drug-users may be switching products, and possibly to ones that are stronger and do more harm.

Dunne has repeatedly said that to his surprise there "seems" to be more stories of harm coming to light, even though the 41 remaining products were meant to be the lowest risk available. But all of that is entirely anecdotal. Where's the empirical evidence?

Here's what's most likely to have happened: The number of shops selling legal highs has reduced from over 3000 to just over 150. The number of sales has concentrated to just a few areas and therefore those sales have become much more visible. Hence the quees down the street in Palmerston North and elsewhere that have so shocked public sensibilities.

But is that a sign that demand has grown? Or that addiction rates are higher?

No, it's a sign that the law is doing exactly what it was meant to do – drive the sale of drugs out of the dark and into the light. A regulated market had been created at a few approved shops, police knew exactly where the sales were taking place and a small marketplace had been created, as per the will of parliament.

Is there any evidence of increased sales? No. Of any greater harm? No. Perhaps the opposite in fact.

Nicola Kean, a producer for The Nation, asked the Ministry of Health last week:

"What’s the trend (if any) for people presenting at A+E for problems with psychoactive substances since the law was introduced?"

A written reply on Thursday said:

"While it is early days the Authority has received anecdotal reports demonstrating the number of severe presentations to emergency departments has reduced since the Act came in.

The Authority monitors approved products received from the Centre for Adverse Reactions Monitoring (CARM), and calls from the public to the National Poisons Centre on a regular basis.

These reports also show a reduction in the number of severe issues being reported. Where severe adverse reactions are reported the Authority has the power to act and has already removed products from the market where reports to CARM identified they posed more than a low risk of harm".

So again the evidence is only anecdotal, but the official line was that if anything reports of severe harm caused by legal highs was DOWN since the law was introduced.

Only it made for bad optics; the public didn't like what it saw. The political risk to the government became too high. Hence the de facto ban via councils becomes a temporary ban via a government-mandated product recall.

Why? Because it has suddenly deemed the legal highs for sale present too a high risk – even though the regime for testing risk hasn't been designed yet. That's plain daft.

So the move to take the remaining legal highs from the shelves is, in short, a knee-jerk amendment based on public outrage, political desperation and supposition. There is no evidence to support it and what anecdotal evidence exists with officials suggests that the bill is working.

And in the end, all this amendment does it buy some time. Two problems remain for the government. First, the court case against Hamilton (and another against Hastings) has a decent chance of success. When you're naming bus stops and even the ever-present Waikato River as "sensitive sites" there's every reason for a judge to find the council has over-reached.

If The Star Trust wins its case, the law is in limbo and politicians – central and local government alike – are back to square one.

And that's the law itself. Which is also the second problem. The fact that no MP can avoid is that last year they voted to create a regulated but legal market for psychoactive substances. It's in the statutes. The judge hearing the case against Hamilton will look at the law, see that the will of parliament was not to ban but to create a legal market and be forced to follow that will. And whatever testing regime the government puts in place, the will remains, saying that it's OK to sell these substances if they can be proved low risk.

As was always going to be case, the risk threshold the government settles on will define what this law really means. If it's set low, similar products to the ones now being removed from shelves will return and public concern will rise again.

If it's set high (so it's almost impossible to prove a product 'low risk'), it will be another way of enforcing a de facto ban. That may well calm public jitters, but it achieves only half of what Dunne and others have said they were fighting for. A high threshold will stop manufacturers tweaking molecules to make their drugs legal. But the demand will remain, and so to the suppliers. They will simply sell the product illegally and the chance to regulate the use of such drugs – to encourage people to seek help when things go wrong, monitor trends and so on – will be gone. The gangs will have another form of income.

That's exactly what the politicians said they didn't want. It's exactly what the law was designed to avoid. The truth is that MPs want a regulated market, but are now running scared from a public they failed to win over and take with them.They are doing their best to undermine the law they voted in – and in their heart of hearts most still support.

But that's not the end of it.

Whatever you see reported today, rest assured the battle over legal highs is far from over while we await the court case and the new regime.

Of course there is one other possible outcome. One of the first manufacturers of legal highs – the King of Legal Highs as he was called – Matt Bowden last year vowed to create new drugs that would be low risk and which would meet any test the government introduced. Bowden made many millions from legal highs through the first decade of this century and is now living life as a rock star called Starboy. But he promised to return when the regime was finally established and to start selling 'low risk' legal highs. Indeed, he said he could make it one of New Zealand's leading export industries in a matter of years and that psychoactive substances could join the likes of dairy and tourism as a major economic earner for this country.

Only time will tell if he's right, or even serious. Is a genuinely low risk drug – which still achieves the sought after high – possible?

In the meantime, we are left with politicians who have had their minds altered by public opinion and an impending election. And that's proof once more that power is a very dangerous drug indeed.