If Democrats keep the White House come November, millions of Americans could gain health-care coverage. If Republicans take it back, millions could become uninsured. A new study ran the numbers under the proposals of both U.S. presidential candidates.

Donald Trump’s pledge to repeal the Affordable Care Act, President Barack Obama’s signature health-care law, would result in 19.7 million more people without insurance and widen the federal deficit by $33.1 billion in 2018, according to an analysis conducted by research group Rand Corp. and funded by the Commonwealth Fund, a nonprofit foundation. The Republican nominee’s proposed tax credits would largely benefit higher-income people, the study also found.

By contrast, one of Hillary Clinton’s key health-reform plans could provide insurance to as many as 9.6 million individuals and lower expenses mainly for low- and moderate-income people. It would come at a greater cost to the budget, increasing the deficit by $90.4 billion.

The report offers a detailed look at the policies pushed by the two presidential nominees in a campaign where ugly rhetoric and controversy have often swamped policy discussions. The Affordable Care Act, known as Obamacare, remains a flash point six years after its passage, with Democrats determined to protect it and Republicans vowing to repeal it. The study, coming days before the first Clinton-Trump debate on Monday night at Hofstra University in New York, puts some numbers behind the heated political debate.

“We’ve heard the discussion of repealing the Affordable Care Act for many years,” said Sara Collins, a vice president at the Commonwealth Fund. “The estimates provide people with an idea of what it means to retain the law versus repeal the law. By just the act of repealing, it would lead to millions of people not having coverage.’’

In a statement, the Trump campaign dismissed the study’s findings as “ludicrous” and criticized its approach as a “distraction from the disaster that is Obamacare.” Any replacement to Obamacare would ensure that those now receiving support would be given subsidies or other forms of help to purchase health insurance in the private market through Health Savings Accounts, the campaign said.

“Hillary Clinton will build on the health care progress we’ve made by expanding coverage to millions of Americans who need it and addressing the costs that families face,” said Jacob Leibenluft, a senior policy adviser to Clinton.

Repealing Obamacare

To evaluate Trump’s plans, Rand modeled the effects of repealing Obamacare and replacing it with his proposals. The Affordable Care Act, or ACA, gave states funds to expand the government-run Medicaid program for the poor, and created markets where individuals could buy health plans, often with federal subsidies. It also lets children stay on their parents’ health plans to age 26, requires the purchase of health insurance, and bars insurers from excluding people who are sick, with so-called pre-existing conditions, from buying plans. Clinton’s plans were evaluated as extensions of the current law.

The researchers said they asked both campaigns to help with the modeling. Clinton’s campaign provided answers, while Trump’s campaign referred the researchers to its website, they said. Both campaigns were given copies of the analysis before it was published.