Researchers at Harvard conducted an exhaustive study last year of things that make health systems in developed countries different from one another. They determined that the United States is distinct in a few ways. But the clear finding of those researchers was that it’s this huge gap in prices, more than any other single factor — not the number of doctors’ visits or hospitalizations, not the quality of medical services, not differences in social service spending — that helps explain why the United States is such an expensive place to be sick. (I wrote an article about that study, if you’re interested in the details.)

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Over the last decade, most of the political health policy debate has been about how to ensure broader insurance coverage for the public. (Another way the United States is unusual is in having so many residents without any form of health insurance.) But the debate among candidates for the 2020 presidential race has begun to tack slightly toward policies that will address price as well.

The single-payer plans Senators Bernie Sanders and Elizabeth Warren have proposed would use a large government insurer to set prices for all medical services. Both campaigns assume substantial savings would result as that government system lowered prices across the board: for doctors, hospitals, medical devices and drugs.

Even plans considered more moderate, like those from Pete Buttigieg, the South Bend, Ind., mayor, and Michael Bloomberg, the media executive and former mayor of New York, would impose some controls on health care prices, by limiting the amount that doctors and hospitals could charge in the situations where they typically charge the most.

President Trump, too, has pushed forward with an initiative to lower prices: Through an executive order and regulation, his administration is seeking to require health care providers to publicize the prices they have negotiated with insurance companies. The idea is to promote more competition through transparency, though researchers are divided on whether the measure will work. (The administration has also worked with bipartisan legislators to eliminate surprise billing, which occurs most commonly in medical emergencies at hospitals, though that effort has stalled.)