The Police Association was out of the blocks early on the pros and cons of this referendum when we made it the theme of last year’s conference, looking at how a “yes” vote would affect policing.

We were congratulated on a “brave but necessary choice” of topic, and feedback from conference delegates was positive, acknowledging that, with attitudes to cannabis changing worldwide, we need to be informed and ready to work with any potential changes to the law.

The point we continue to emphasise is that the association is neither for nor against a change to the status quo. As police, we enforce the law whether we personally agree with it or not.

Also, as police, we are well aware of the risks associated with cannabis consumption, which is why this debate must be factual in its assessment of the educational, health and societal aspects of a potential law change.

Statistics show that apprehensions for cannabis use declined by 70 per cent between 1994 and 2014. Warnings now far outweigh arrests, as police discretion is increasingly acknowledged as appropriate, particularly for young people with small amounts of cannabis.

The 2020 referendum will be a yes/no vote on a draft bill outlining the proposed law, which will include an age limit of 20 years, restrictions on homegrows, where cannabis can be sold and consumed and a ban on advertising. A “yes” vote would mandate the incoming government to enact the bill, or discard it, irrespective of the poll result.

We’ve been watching how Canada is coping with cannabis reform – in the lead-up to its legalisation last October, and subsequently.

Earlier this year, I attended a symposium at which Eric Costen, the health official who spearheaded the design, development and implementation of Canada’s legalisation process, outlined the necessity for an early and sustained public education and consultation process.

He said the complexity of the issue meant policy goals needed to be clearly articulated, with data published, and, if the law changed here, we should all be prepared for a period of transition and adjustment.

New Zealanders should not underestimate how polarising this debate will be. Already, extreme views from both sides are making headlines, indicating we will all have to do our homework to be informed by fact-based and balanced sources.

How to assess impairment is a big issue for me, and Dr Costen admitted they do not yet have a scientific measurement for that. THC may remain in your blood for days or weeks after using cannabis, but does that mean you are impaired? That has potential ramifications for officers who might legally use cannabis off duty and then test positive in a compulsory post-critical incident drug and alcohol test.

Drug-driving is another biggie. The Government has just released a discussion document on that and the association will be making submissions, because the outcomes affect us directly in terms of roadside testing and resources for expensive equipment and training.

Canada’s Minister of Border Security and Organised Crime, Bill Blair, summed up the legalisation journey extremely well, saying: “It is a process, not an event.”

We are beginning to know exactly what he meant.