You also heard a debate about fairness and choice. Giving all Americans access to the same housing arrangements means that no one will have to live in a cramped attic. But it also means that some family members will have to part with some of their favorite furniture. “Of the 160 million people who like their health care now, they can keep it,” said Mr. Biden, of the virtues of his fixer-upper proposal. “If they don’t like it, they can leave.” By contrast, Ms. Warren emphasized the universal nature of a teardown approach: “We’re going to do this by saying, everyone is covered by Medicare for all; every health care provider is covered.”

The “Medicare for all” system envisioned by Mr. Sanders would cover more benefits than nearly any system in the world, but it would require everyone to have the same type of insurance, with no easy workarounds for patients who aren’t satisfied. Ms. Harris’s plan would allow more choice, letting private plans operate alongside the government system. But those tightly regulated products would not be allowed to differ nearly as much as plans that exist in today’s system and would also amount to a brand-new system.

The candidates also disagree on how people should finance their ambitions. The fixer-upper candidates, for the most part, favor a system in which most Americans would still need to pay some form of rent to live in the house. The teardown candidates think everyone’s housing costs should be financed by taxes instead of direct payments.

A tax-financed system would mean big changes in who pays what for health care, and how. A system that preserves a mix of taxes, premiums and direct payments like deductibles would mean less rearranging of the financing of health care and would probably require more modest tax increases.

This is only a metaphor, of course. There are many ways the health care system is not like a residence. But if you’ve ever renovated or built a home, you know the emotional and budgetary stakes. The health care system is personal to many Americans, just like their home. It’s no surprise the debate has been so heated.