Buried away in a Commons debate the other day was a remark that could apply to the unhealthy state of the economy and assorted remedies to cure it, including a large injection of job-boosting cash into the NHS capital building programme.

We'll learn more about that when Alistair Darling unveils his pre-Budget report on Monday. Cautious scepticism is in order until we do.

But the economy is not the only stretch of uncharted water the country has to navigate. The remark I spotted came from Tory barrister-MP Edward Garnier, explaining that "the law must be certain as to its meaning and effect". Quite so. What will the effect of Darling's economic medicine be?

But what law was Garnier discussing? All of them, the QC said, though he was talking specifically about the Suicide Act 1961 and the latest attempt to revive Lord Joffe's campaign to permit "assisted dying" for the terminally ill. Where does society draw the line? It is a shock to be reminded that in the five years before the 1961 reform, 3,000 people were prosecuted in Britain, not for helping someone commit suicide - the issue today - but for the God-denying crime of attempted suicide. Some 200 went to jail.

In the 1950s Baby P's killers might well have been hanged for murder in Haringey. Tough? But that generation would regard our own lax attitudes towards drink, drugs and sex with equal horror.

In the thick of the fray as usual is Baroness Warnock, the Oxford philosopher. Not content with supporting assisted dying ("if you're demented you're wasting people's lives"), she takes sides in other sensitive controversies. Thus she endorses the doctrine of presumed consent (we have to opt out instead of opt in) which would allow the NHS to use your organs, Spanish-style, for transplant purposes. The UK organ donation task force warned ministers this week it will not work.

Undeterred, Baroness Warnock also urges "Nanny State" (her words) to reject the cries of libertarians and take a firmer stance against excess, be it smoking, boozing, drugs or prostitution. "If you can't find consensual sex, try masturbation," she sternly advised Observer readers. But few of us are that confident, certainly not most politicians who want to get re-elected.

Evan Harris, Lib Dem MP for Oxford West and Abingdon, is an exception, perhaps because he has such highly educated constituents. So it was his Commons debate Edward Garnier was addressing.

Uneasy cases

Dr Harris makes a good case: unlike would-be suicides, assisted dying is for people who want to live, but have no hope of anything but pain. Personally, I share it. But opponents of the well polished "slippery slope" towards euthanasia argument make telling points too.

We can all be impressed by Debbie Purdy, the 45-year-old MS sufferer who went to court to try and ensure that if her husband takes her to the Dignitas clinic in Switzerland he will not be risking 14 years in prison, as the 1961 act stipulates.

Likewise by brave Hannah Jones (13), who went to court to stop her hospital trust making her have a heart transplant. But many people (including me) were uneasy about the case of Daniel James (23), the injured rugby player taken to Dignitas with his family's help just 18 months after his accident.

Debbie Purdy's judge said "Parliament must decide". Harris says uncertainty is wrong. Garnier agrees without expressing a view. The law is clear, but its effect is not: few people are prosecuted for assisting consensual death; very few of the estimated 900 doctors who help patients die each year.

But the threat of legal action remains. So do passionate views. MPs in all parties spoke both to support and oppose Harris. All three Lib Dems took different views, including John Pugh, who spoke against his party's pro-Harris policy.

So for every Washington state which this month voted by referendum to follow neighbouring Oregon in doctor-assisted suicide, a California, Michigan and Maine all voted against it. No safeguard is ever strong enough, they argue.

Harris thinks that Alan Johnson's views are rational, what he regards as untainted by religion. But the health secretary will only move to consult voters (as the Law Commission proposes) and further clarify the law if Gordon Brown gives the nod, as he did on top-ups. I'd say Brown has quite enough on his plate.