This week my brother, Bernie Sanders, won the Wisconsin Democratic primary – which is great news. But it is also great news for a central and defining issue in his campaign, which is the shambles that is American healthcare.

The strangest thing about the debate over healthcare in the US is that it is still going on. The system’s failure is glaring. Millions have inadequate care and tens of thousands die unnecessarily. Average life expectancy is lower than that in dozens of poorer countries, and more children die and more people have chronic diseases than in other rich countries. People pay vastly more than in any comparable economy, and their lives are dominated by the fear of falling ill, of being unable to protect their children, of having to choose between buying insurance and having enough for rent or mortgage. And then, when serious illness develops – often because early treatment was not affordable – they face grinding financial worries on top of the illness itself. A million people a year are bankrupted by health debts.

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It is not difficult to see why the beneficiaries of this failing system support it, as astonishing amounts of money can be made. The chief executive of United Healthcare, the largest insurer, for instance, was paid $66m in 2014. But why do so many people vote for politicians, including Hillary Clinton and Ted Cruz, who argue that the US cannot have a high-quality universal system? Much of the reason comes from the normal working of a very unequal system. Wealthy executives and shareholders can finance intensive lobbying and contribute to election campaigns.

The founding principle that “all men are created equal and are endowed by their creator with certain unalienable rights” could have led to good healthcare being available to everyone. This is what my brother argues: that “healthcare must be recognised as a right ... regardless of their income”. The belief in equality is deep in American society, but it is challenged by a conviction that government support is morally dangerous for the individual and an assault on the rights of those whose taxes pay for the benefits. In fact, while over 60% of the healthcare budget is provided from taxes, the problem is how little of it actually pays for care.

Facebook Twitter Pinterest Green Wing cast members support the junior doctors’ strike. ‘Obamacare is an inadequate alternative. It helps some people get insurance but it doesn’t guarantee coverage: 30 million are still not covered for healthcare.’ Photograph: Nick Ansell/PA

The private insurance industry siphons off hundreds of billions of healthcare dollars for overheads, profit and administration. It has little incentive to control costs because higher costs allow it to increase charges proportionately. Pharmaceutical prices are much higher than in systems with powerful centralised purchasers. Reducing these prices to European levels would save more than $100bn a year. Patients with inadequate or no insurance are given expensive care in emergency rooms, having failed to get timely attention.

The high cost is not due to more doctors and hospital beds: there are far fewer of both per capita than in most other rich countries, and they are used less frequently. Expensive technology is employed much more often as competition means providers must appear to be up to date. There is also a perverse incentive for profit-makers: the more they sell, the better they do – two procedures are better than one. The National Academy of Medicine estimates that unnecessary care given to well-insured patients cost $210bn in 2009.

The entire system is riddled with waste of this kind. It is hard to see a solution that is not a publicly financed, universal and not for profit.

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Obamacare, though an improvement, is an inadequate alternative. It helps some people get insurance but it doesn’t guarantee coverage: 20 million people have been able to get insurance; 30 million are still not covered for healthcare. Insurance companies are still allowed to limit benefits, medical providers and care; they can (and do) increase patients’ co-pays (the fee paid each time treatment is accessed) and other out-of-pocket costs. The system adds further layers of administration to the current mess, and increases the scope for profiteering.

A truly universal system would be financed by progressive taxation, but under Obamacare costs continue disproportionately to be paid by middle-and lower-income Americans and those facing acute or chronic illness.

The struggle between profit and good quality healthcare for all cannot stop. Too much money and a decent society are at stake. British people notice that we have too few doctors in the UK and too few nurses and hospital beds. Britain too squanders billions on administration and privatisation. But many Americans are fighting for what the UK has. We must campaign to preserve and restore the NHS, which despite its challenges works well as a service and helps bind us together as a society.