Mr. Trump is running for re-election this year, so his budget can be read as a policy blueprint for his second term if he wins. The budget leaves to the imagination just what that vision is. Unlike in previous years, when the health care budget laid out specific plans to repeal large sections of the Affordable Care Act and replace it, this year’s proposal barely mentions President Barack Obama’s signature health care law.

But the deep cuts enshrined in the budget’s numbers are not consistent with modest tweaks. Taken together with Medicaid changes recommended elsewhere in the budget, the proposal would strip about $1 trillion out of Medicaid and the Affordable Care Act’s premium subsidies, the two pillars of the law’s expansion of insurance coverage. By 2029, the cuts to those programs in Mr. Trump’s budget would represent around 85 percent of the total that the Congressional Budget Office estimates would otherwise be spent on Obamacare coverage that year.

Aviva Aron-Dine, the vice president of health policy at the progressive Center on Budget and Policy Priorities and a former Obama administration budget and health care official, said that she found the magnitude of cuts difficult to square with the budget’s language.

“You can’t cut $1 trillion from these programs and protect the most vulnerable,” she said.

Mr. Trump began his presidency with a promise to repeal the Affordable Care Act, but efforts to do so in 2017 were unsuccessful. Despite Republican control of both houses of Congress, legislators were unable to agree on an approach. The Senate tried and failed to pass several different bills that would have reshaped big parts of the 2010 health law.

With Democrats making health care central to their 2020 campaigns, Mr. Trump has been facing pressure to propose his own health care overhaul. He has repeatedly promised to release one. The administration is backing legal action pressing to declare the entire health law unconstitutional, and if it wins in court, the result could be a wave of disruption as an estimated 20 million Americans lose health insurance, insurance consumer protections crumble, drug approval pathways disappear, and Medicare fraud statutes are weakened, among many other effects.