Last week, Interim Conservative Leader Rona Ambrose announced that unless Bill C-14 on physician-assisted dying increases protection for vulnerable people, she'll vote against it. Why is it that when able-bodied, healthy people are called on to assist people with disabilities or illnesses they always assume they're supposed to protect them? There are other options.The "No means no" campaign is a good example. It reduces women's vulnerability to sexual aggression, but not by adding more layers of protection. Instead, the rule empowers women by increasing their control over sexual relationships. Those debating physician assisted dying could learn a lesson from this.The first step is to recognize that, when it comes to assisted dying, people with physical or mental illnesses are vulnerable in different ways. For example, people with psychosis or advanced dementia are unable to make a sound decision on assisted dying, as are young children. If there were no constraints, these people might make a disastrous mistake.Assisted dying thus poses a clear danger to them that calls for protection. But I don't think anyone of note denies this. Certainly, the Supreme Court doesn't. The Carter decision restricts assisted dying to competent, consenting adults—and that brings us to the real debate over vulnerability.Critics of the Carter decision see disaster written all over it. Chronic physical or psychological suffering, they say, could make people susceptible to social or family pressures to end their lives. Intense depression might cloud someone's judgement. Advance consent might fail to register a change of heart. With all these things going on around a decision to die, the critics ask, how are doctors supposed to know when consent is valid?The question is supposed to be rhetorical. The prospect of so many people making bad decisions is assumed to discredit the Court's approach. Competence, insist opponents, is an unreliable way of distinguishing between those who need protection and those who do not. Its use should be narrowly circumscribed.Many advocates of assisted dying find this line of argument outrageous and patronizing. In their view, it amounts to saying that if you are not able-bodied or healthy, your judgement on assisted dying cannot be trusted. Why, they wonder, do able-bodied and healthy people get to make such a presumption about the mental competence of people with illnesses or disabilities?I think the advocates have a point. Opposition to assisted dying seems to be led by a coalition of mainly able-bodied, healthy people who claim to speak for the sick and disabled. On one hand, they insist that what most of these people need is protection, not choice. On the other, there is very little willingness to discuss how this "protection" condemns them to a life of suffering.Of course, advocates don't dispute that competence can be controversial. After all, people often are ambivalent about dying, insisting at one time that they wish to die, then at another that they don't. There are real questions about the degree of certainty required before consent is valid.Most supporters of assisted dying agree that high levels of uncertainty should disqualify someone from an assisted death. But they also accept that adequate tests can be devised to detect this. These decisions may be complex and layered, but medical experts are not totally in the dark.In my opinion, the advocates' arguments are far more convincing than the opponents. The latter seem to be saying that, in order to be valid, a decision to end one's life must be unencumbered by external influences or ambivalence. This seems to fly in the face of how our psychology works.A person contemplating death will be weighing all manner of things and will almost certainly have doubts along the way. It would be strange if they didn't. This is the most important decision they will ever make and their life quite literally hangs in the balance. Nevertheless, this kind of ambivalence need not render a decision invalid. The "No means no" rule helps us see why.Like assisted dying, sexual engagement can be a complex and even threatening affair where consent is often in question. A woman in this situation may be ambivalent about whether she wishes to proceed. However, by reducing her vulnerability the rule empowers her. Saying no establishes a clear standard for subsequent behavior—even if her actions continue to convey uncertainty. Unless and until there is an explicit retraction, no means no.The lesson for assisted dying is that clear decisions need not exclude ambivalence. To be a competent decision-maker one does not have to dispel all doubts or be free of external influences. Such a condition is likely unattainable. In the case of assisted dying, it is enough that the decision be deeply considered; and that the person has resolved to carry through on it, even in the face of uncertainty. Where these conditions are met, yes means yes.In sum, the current debate over assisted dying blurs two very different ways that people can be vulnerable. In one case, they are vulnerable to an untimely death brought on by an unsound decision. Here protection is appropriate.In the other, they are vulnerable to a life of irremediable suffering. Having the choice to escape from it can be enormously liberating, not only for those who choose this path, but also for those who don't. A decision to live with one's suffering, freely made, can give such a person a renewed sense of control over their life. And that, in turn, can be genuinely and deeply empowering.Dr. Don Lenihan is Senior Associate, Policy and Engagement, at Canada 2020, Canada's leading, independent progressive think-tank. Don is an internationally recognized expert on democracy and Open Government. He is currently the Government of Ontario's principal advisor on its Open Dialogue Initiative. The views expressed here are those of the columnist alone. Don can be reached at:[email protected] or follow him on Twitter at: @DonLenihan