When voters deliver a wham-bang walloping rejection, what do you do? Offer them more of the same warmed up next time – or change direction entirely, reinvent yourself and begin again? Nick Clegg and his battered fellow hostages inside government stand at that pivotal moment. A burning-rubber U-turn is never a pretty political sight, but it is the only option that might, just possibly, avoid sudden death.

Clegg looks as if he has got the message. After last week's double calamity he has bounced back with a newfound determination to become saviour of the NHS. With a somersaulting, word-swallowing volte-face, he looks ready to tear the heart out of the Lansley-Cameron NHS bill. Has he got the nerve to see it through – or will he accept a little cosmetic surgery?

Weakened to the point where Tory backbenchers call for the Lib Dems to be ignored from now on, Clegg looks as if he has no hand to play. Walk away, and a general election will finish off the party. Cling like chewing gum to Cameron's shoe, and he looks downtrodden. If he makes strong demands now, some Tory hotheads are yearning for an excuse to call a snap election and flick this irritant off their soles. But there is just one issue on which Cameron could never call an election: the NHS – where he knows his party is never trusted.

He could lose an election caused by a rift with the Lib Dems over this, pitched against Labour and all the NHS professions, the doctors, nurses and patients' organisations accusing the Tories of planning wholesale privatisation: chapter and verse is there in the bill to prove that is indeed what they intend.

Shirley Williams broke ranks to stir up the Lib Dems against the bill, igniting their conference rebellion. Late, Clegg picks up the baton – but only on this bill, which already hangs in a strange limbo, enjoying a "natural break" halfway through its progress. Perversely, Cameron may be saved from his own stupidity if the Lib Dems do sterilise the bill.

The amendments drafted for the Lib Dem conference by former MP Dr Evan Harris in effect eviscerate the plan. It is murder with a scalpel, leaving a ghost of the Lansley changes as they appeared innocuously in the coalition agreement.

Lansley's spin was that his revolution was all about handing commissioning to GPs: letting your family doctor buy the treatment that is right for you sounded so reassuring. But beneath the skin the meat of the bill lets every part of the NHS out to "any willing provider". Cleverly, the Lib Dem amendments leave GPs nominally in charge – but only where they choose to be, with primary care trusts remaining elsewhere, closely overseen by councillors, nurses and others. Lansley's face could be saved, just, while the guts of his reforms are purged.

Here are the Lib Dem red lines to stop the breakup of the NHS – and they are radical. GP consortiums or PCTs must never be outsourced, stopping the 14 private companies already signed up to take on commissioning. Consortiums will be subject to freedom of information, they will include elected councillors, and be linked geographically with councils so they work together with social services. Any unpopular decisions, such as hospital closures, can be referred ultimately to the secretary of state. (The bill planned for the market and regulators, not parliament and ministers, to bear ultimate responsibility.) Foundation trusts will get no extra freedoms.

Most important of all, no competition will be allowed that risks opening the NHS to European competition law, which would force all services to be sold on the open EU market. No bidders can cherrypick profitable services if it leaves existing NHS services financially non-viable. Competing on price for existing tariffs is ruled out "completely". The regulator, Monitor, must put equity before competition. No GPs can garner profit for themselves, their firms or families as a result of their commissioning decisions: already many have set up subsidiary services where they stand to gain.

These wrecking "amendments" would tighten, not loosen, the unity of the NHS, encourage co-operation more than competition, putting accountability before the market. This rows back from what some Blairites had in mind, as described by Alan Milburn in the recent edition of Progress magazine. This demolishes what David Laws and others advocated in their Orange Book – an insurance-based NHS. So will Clegg press for the reforms his party has demanded? He will have to eat a huge helping of words, but he has no comfort zone. He signed up to the Orange Book and with Cameron he signed this bill. Even when it was sent, under fire, for review by Oliver Letwin and Danny Alexander, it came back with his renewed support.

In a scramble of a debate in the House of Commons today, three-way insults flew about who supported what and when: New Labour accelerated competition, brought in private treatment centres, paid them a premium and left half-empty wards. Labour would have cut the NHS even more, and so on. But this is the moment for all three parties to abandon their past. Labour can hardly allow itself to be outflanked by the Lib Dem amendments.

However, ideological arguments about who first marketised how much of the NHS are about to fade into insignificance. The bill will be drowned by the coming NHS crisis. Whoever is then health secretary will be overwhelmed by the financial crunch sweeping towards the service as its full force hits hospital wards, community services and GP surgeries. No 10 has just called in one of the wisest NHS analysts, Prof Alan Maynard, who will tell them what Stephen Dorrell keeps saying. Productivity gains are hard to force out of the system in a hurry. It takes what Maynard calls "Stalinist central control", forcing the NHS to obey Nice guidelines on the best and most cost-effective practice for everything.

Monitor now says the NHS must save not 4% but 7% a year for the next four years – causing cardiac arrest after the annual 7% extra injected by Labour. Wards will close with staff fired as waiting lists soar: the NHS has never had such cuts. The news will shock just after patients recorded highest ever satisfaction last year, as waiting lists vanished. It may be a bit late now to listen to Maynard's doom-filled warnings. All parties need to rethink their recent past, but Nick Clegg has most to repent fastest.