More than 40 million people, including 10 million children - at least 15 per cent of the US population - have no health insurance, latest estimates suggest. They are mainly the working poor, who must pay for their care or go to public hospitals' emergency departments, which legally may not refuse treatment. They receive less and lower-quality medical care than other Americans, according to Dale Tussing, a professor of economics at Syracuse University.
The US has the world's most expensive and technologically advanced healthcare system, yet it fails to provide adequate care for a sizeable minority of its population.
The minority of the population who vote generally have good healthcare. Politicians receive campaign funds from political action committees linked to lobby groups, 500 of which represent healthcare interests.
Whereas European states have in general opted to fund healthcare by general taxation, as in the UK, or by compulsory social insurance, as in Germany, in the US healthcare is provided by private voluntary insurance.
The government does not pay for healthcare except for older people and disabled, through Medicare, and the very poorest, through Medicaid, which covers just 40 per cent of those below the poverty line. The rest of the population is covered by employer-provided benefit schemes - which not all employers offer - or hugely expensive private insurance, or remains uninsured.
The many tiers of US healthcare go beyond the four of Medicaid, Medicare, uninsured and insured. With competing profit-motivated insurance companies, access to care differs from insurer to insurer, state to state and year to year. Hospitals are voluntary non-profit (55 per cent), public (27 per cent), federal (5 per cent) or for-profit (13 per cent). The concept of a GP is alien to Americans, who expect direct access to specialists.
Physicians have traditionally been self-employed and the highest paid professionals in the US, with an average income in the mid-1990s 10 times that of the average production worker. Irish public-hospital salaries for consultants start at £87,000, and with private practice frequently exceed £200,000, sometimes greatly, while industrial workers in the Republic earn an average of just over £19,000. Of the 13 per cent of its GDP that the US spends on healthcare, between one and two percentage points go to the profits of insurance companies and medical-care organisations - 1 to 2 per cent of the country's entire income.
Spending on healthcare in the US massively exceeds spending in Europe (see main graph). Even its public-health spending per capita exceeds total health spending per capita in Europe. Yet life expectancy is lower than the European average, while neighbouring Canada, which spends 9 per cent of GDP on healthcare, delivers equitable access and has a life expectancy above the European average.
Unsuccessful efforts to introduce compulsory social insurance to cover the entire US population began in the 1910s. Supporters of compulsory social insurance included President Truman in the 1940s, Senator Ted Kennedy in the 1970s and the Clintons in the 1990s. Opponents included doctors, hospitals, employers and insurance companies.
Medicare and Medicaid were introduced in the 1960s. From the 1970s, employers and insurance companies sought to control costs through so-called "managed care" by bodies such as health maintenance organisations (HMOs), which pay physicians a salary or a fixed sum for each patient rather than on a fee-for-service basis. The Clintons proposed to combine managed care with German-style compulsory workplace insurance while retaining for-profit hospitals, health insurers, HMOs and physician practices. Yet this was still labelled "socialised medicine" and failed to win the support of Congress.
Some states, such as Hawaii, Massachusetts, Oregon and Minnesota, have sought with mixed success to cover the uninsured, through measures such as expanding Medicaid or offering affordable insurance. Conservative states such as Texas, on the other hand, have very low eligibility for Medicaid. A new federal programme to help states provide for uninsured children has reached only three million of the 10 million young uninsured.