By Alex Penk

After months of thought and argument, the justice select committee has thrown the End of Life Choice Bill back in Parliament's lap.

We're in the strange situation where no-one, not even sponsor David Seymour, is supporting the Bill as it is. The select committee couldn't agree that the bill should pass and made only technical changes to it, deliberately leaving major questions hanging. Supporters are trying to invest the procedure with the illusion of certainty, but the bill is now overshadowed by ambiguity.

Seymour has stated that, if the Bill passes its second reading, he will propose an amendment limiting eligibility under it to patients with terminal illnesses. But he has also said his amendment would introduce eligibility for neurodegenerative conditions that are likely to cause death within 12 months, alongside the current provision that has a six-month limit.

This example shows that amending the Bill would be messy, with MPs voting on a patchwork of proposals that are unlikely to add up to a coherent, watertight law. Not only would each MP vote based on their individual conscience, but party agendas would be at play too. In particular, NZ First has stated that the issue should be subject to a binding referendum and may refuse to support any Bill without it.

But let's imagine that, somehow, the stars align and a cut-back, workable law is passed. Even a narrow version of the Bill creates a risk of wrongful death: deaths that would fall outside the Bill's own criteria. For example, the Bill is based on the ideal of free and informed consent, but the select committee noted submissions from doctors that "determining whether a person is competent [to consent] is complex, challenging, and subject to error ... a person's competence can vary daily, particularly if they are suffering from a terminal illness".

There's also a risk that some people would choose euthanasia because they felt pressure from others, and fear of being a burden was a reason for choosing assisted suicide for 63 per cent of patients in Oregon last year – a trend that has been rising steadily.

There's also no reason to think the law would be set in stone. For example, Belgium introduced a euthanasia law in 2002, then expanded it to terminally ill children in 2014; and after just over two years, the Canadian Government is considering whether to expand its euthanasia law to "mature minors". Our attorney-general, in his report on the Bill, said that limiting eligibility to over-18s was inconsistent with the New Zealand Bill of Rights Act and that consistency would require lowering the age limit to 16 or removing it altogether.

Whatever form the law took, creating legal assisted suicide would confront every eligible person with an entirely new question: is my life worth living? Should I hang on, or end my life now? It's a question that becomes an undercurrent in conversations with doctors and family members.

These risks are why it's so uncommon for law-makers to allow euthanasia or assisted suicide. The Bill's supporters like to tell us that 150 million people worldwide have these laws, but this is a tiny fraction of the global population, and euthanasia Bills are still being voted down more often than they pass in jurisdictions around the world.

Our MPs should follow this example and vote against the Bill.

* Alex Penk is chief executive of the Maxim Institute, an independent think tank.