When experts talk about the crisis in America’s health care system, two culprits are often the focus: double-digit yearly increases in costs and the 45 million people who lack insurance.

The problem, however, goes much deeper. A new study from Harvard University researchers has found that about half of all personal bankruptcy filings in the United States are the result of unpaid medical bills. Even more disturbing, a majority of those bankruptcies were middle-class homeowners who had health insurance, at least at the start of their illness.

The researchers draw four conclusions from their study:

• Even brief lapses in insurance coverage may be ruinous.

• Many health insurance policies don’t provide enough protection from serious illness and injury.

• Even good employer-based insurance plans might not provide enough protection because illness and injury can lead to job loss and dropped coverage.

• Injury and illness, in addition to causing a person to incur medical bills, can lead to a reduction of income, which makes the debt problem more difficult to overcome.

Simply put, a serious illness can begin a downward financial spiral for people who don’t fit the spendthrift stereotype sometimes associated with filing for bankruptcy.

According to the study, published earlier this month in the medical journal Health Affairs, the typical debtor might look too familiar for comfort: A 41-year-old woman with children, some college education, a home and yearly income around $25,000 a year. The average amount of medical debt that started the bankruptcy was $11,854. Three out of every four had insurance when their medical problems began.

For too many people, bankruptcy is just a serious accident or medical emergency away.

While the evidence mounts to the causes of bankruptcy, Congress, in three out of the past seven years, has tried to make it more difficult for individuals to receive protection from their creditors. It’s likely there will be another push this year to limit the number of people who can qualify.

Banking and credit card companies are the biggest supporters of tougher rules, citing a rapid increase in filings. Between 1990 and 2003, bankruptcies more than doubled to 1.5 million a year.

Instead of working to ease the considerable strain on families, struggling to grasp that middle-class ring on life’s ladder, the current attitude among many in Washington and Augusta is to make matters worse.

While President Bush’s tax cuts run up the deficit and the national debt, he looks to social programs, many focused on helping the working people, to dry up the red ink. Even then, the numbers don’t balance. The painful cuts are just a distraction from the real culprits: war and tax cuts.

And Dirigo Choice, an innovative if risky proposal to increase the number of Mainers with insurance and slow the escalation of medical spending in the state, must be constantly defended from ideologues who hate it so much they would kill it in the crib before it has a chance to attract participants and grow into a successful program.

It’s scary that a sudden illness or freak accident could leave a family bankrupt. Until the country tackles the flaws in the way most people receive health care coverage, that hard truth will remain.