At a community enrollment drive in the 1950s for Blue Cross and Blue Shield in Oklahoma, Ralph Rhoades, left, a manager who later became president of the plan, greeted a new member. Credit Courtesy of Blue Cross Blue Shield of Oklahoma

The basic structure of the American health care system, in which most people have private insurance through their jobs, might seem historically inevitable, consistent with the capitalistic, individualist ethos of the nation.

In truth, it was hardly preordained. In fact, the system is largely a result of one event, World War II, and the wage freezes and tax policy that emerged because of it. Unfortunately, what made sense then may not make as much right now.

Well into the 20th century, there just wasn’t much need for health insurance. There wasn’t much health care to buy. But as doctors and hospitals learned how to do more, there was real money to be made. In 1929, a bunch of hospitals in Texas joined up and formed an insurance plan called Blue Cross to help people buy their services. Doctors didn’t like the idea of hospitals being in charge, so some in California created their own plan in 1939, which they called Blue Shield. As the plans spread, many would purchase Blue Cross for hospital services, and Blue Shield for physician services, until they merged to form Blue Cross and Blue Shield in 1982.

Most insurance in the first half of the 20th century was bought privately, but few people wanted it. Things changed during World War II.

In 1942, with so many eligible workers diverted to military service, the nation was facing a severe labor shortage. Economists feared that businesses would keep raising salaries to compete for workers, and that inflation would spiral out of control as the country came out of the Depression. To prevent this, President Roosevelt signed Executive Order 9250, establishing the Office of Economic Stabilization.

This froze wages. Businesses were not allowed to raise pay to attract workers.

Businesses were smart, though, and instead they began to use benefits to compete. Specifically, to offer more, and more generous, health care insurance.

Then, in 1943, the Internal Revenue Service decided that employer-based health insurance should be exempt from taxation. This made it cheaper to get health insurance through a job than by other means.

After World War II, Europe was devastated. As countries began to regroup and decide how they might provide health care to their citizens, often government was the only entity capable of doing so, with businesses and economies in ruin. The United States was in a completely different situation. Its economy was booming, and industry was more than happy to provide health care.

This didn’t stop President Truman from considering and promoting a national health care system in 1945. This idea had a fair amount of public support, but business, in the form of the Chamber of Commerce, opposed it. So did the American Hospital Association and American Medical Association. Even many unions did, having spent so much political capital fighting for insurance benefits for their members. Confronted by such opposition from all sides, national health insurance failed — for not the first or last time.

In 1940, about 9 percent of Americans had some form of health insurance. By 1950, more than 50 percent did. By 1960, more than two-thirds did.

One effect of this system is job lock. People become dependent on their employment for their health insurance, and they are loath to leave their jobs, even when doing so might make their lives better. They are afraid that market exchange coverage might not be as good as what they have (and they’re most likely right). They’re afraid if they retire, Medicare won’t be as good (they’re right, too). They’re afraid that if the Affordable Care Act is repealed, they might not be able to find affordable insurance at all.

This system is expensive. The single largest tax expenditure in the United States is for employer-based health insurance. It’s even more than the mortgage interest deduction. In 2017, this exclusion cost the federal government about $260 billion in lost income and payroll taxes. This is significantly more than the cost of the Affordable Care Act each year.