The first debate exchange captured the battle within the Democratic Party over how the presidential nominee should change the country’s health care system.
Some Democrats are proposing a government alternative to private insurance. But allowing people to choose such a plan may destabilize the A.C.A., some experts say.
Ms. Harris is forging her own path on the health care issue, putting forth a plan for providing Medicare for all Americans that stops short of the complete overhaul Bernie Sanders has proposed.
The so-called Cadillac tax on high-cost health plans, a key way the Affordable Care Act was supposed to pay for itself, was dealt a blow by an unlikely foe: Democrats.
Mr. Biden, detailing his health care plan in Iowa, paraphrased a notorious promise made by Mr. Obama: “If you like your private insurance, you can keep it.”