WASHINGTON

Impressed by President Trump’s campaign promises to make health care more affordable, Mavis Reivis crossed her fingers and voted for him.

But the 52-year-old Richmond resident and millions like her are now facing reality: The new GOP health care plan that President Trump endorses to replace the six-year-old Affordable Care Act, or Obamacare, is likely to rip away their health coverage.

The “Trumpcare” plan that House Speaker Paul Ryan unveiled Monday and is now seeking to push through the Congress over the next month, would eliminate the subsidies that have helped Ms. Reivis and others secure comprehensive coverage and replace the subsidies with smaller tax credits that would put the cost of insurance out of reach.

The plan also calls for shrinking Medicaid coverage for low-income adults who cannot afford any policy and eliminating specialty women’s health services, despite President Trump’s promises of providing a better, more accessible health program that would benefit everyone.

Obamacare allowed 20 million people to gain insurance coverage, including 11 million people who have benefited from the expansion of Medicaid in 33 states.

Early analysis of the GOP plan suggests that 6 million to 10 million people would lose health insurance, with suggestions that those numbers would increase because of people whose employers do not provide health benefits.

“My employer doesn’t provide coverage,” Ms. Reivis told the Free Press on Tuesday.

She is a restaurant hostess and cashier and pays for her own insurance through the ACA.

“I’m scared about what is being proposed because I could lose what I have. I don’t want to think about not having insurance at my age. But that’s what could happen,” she said.

With earnings of about $360 a week after taxes, she said she now strains to pay the $270 a month that is her share of her comprehensive health insurance. She said she is grateful that, through the ACA, the government pays the remainder of the cost — about $720 a month — particularly because she recently was diagnosed with kidney disease.

Ms. Reivis was hoping that President Trump could come up with a way to reduce her personal cost.

However, under the House plan, she would receive $3,500 in tax credits, or $5,140 a year less than the $8,400 in annual subsidy the government now provides to assist in the purchase of her insurance.

“From what I’m hearing, I won’t be able to afford insurance. And then my doctors won’t see me,” said Ms. Reivis, who is starting to feel betrayed by a president who campaigned on the promise that “we’re going to have insurance for everybody,” with coverage that would be “much less expensive and much better.”

Indeed, experts indicate the only winners from the Republican plan are likely to be businesses that do not offer health insurance and wealthy individuals and couples with incomes of $200,000 or more a year.

Both groups have been taxed to help pay for the ACA and now would have those taxes eliminated if the ACA is repealed. That’s a collective estimated gain of $600 billion over 10 years in reduced taxes, according to analysts.

The only good news for Ms. Reivis and others who could be booted off insurance is the fact the “replacement” plan has been met with strong resistance, including from Republican members of Congress. Observers say the plan may not pass both houses of Congress, which would be a shocking rebuff to the president and his allies who hold majorities in Congress.

Among the early foes of the plan is GOP Rep. David A. “Dave” Brat of Henrico County, a Tea Party member who wants to rip out the ACA root and branch and leave health care to the states. He has said the ACA is too costly. However, he pronounced Trumpcare “dead on arrival” in the House a day after it was unveiled.

Rep. Brat said Tuesday he and fellow GOP members of the Freedom Caucus are not going to support a bill they view as “Obamacare Lite,” or a plan that keeps much of the ACA intact, including popular items like mandating coverage of people with pre-existing conditions and allowing children to stay on parents’ policies until age 26.

For Rep. Brat and other caucus members, the refundable tax credits appear to be government subsidies that would add to the nation’s $20 trillion deficit. He said the credits are just another entitlement program the country cannot afford.

Conservative donors like the Koch Brothers have announced plans to lead a media campaign to attack the plan and urge a simple outright appeal of the ACA, which is what they say Republicans promised to do.

Meanwhile, more moderate GOP representatives are skeptical about a plan that would eliminate health insurance for so many.

Republican Sen. Susan Collins of Maine is among those indicating they cannot support the bill because of the huge numbers of people who would lose insurance coverage and the likelihood that the premiums would skyrocket, particularly for older people.

The Republican plan would allow insurance companies to charge people age 50 and older five times as much for a policy as those who are younger.

Opposition also is coming from Republican governors, many of whom have supported the ACA and the expansion of Medicaid based on the government’s promise to cover 90 percent of the cost. Under the Republican plan, Medicaid reimbursement would be slashed by 2020 and fewer people covered with federal payments, leaving the states to pick up the difference.

Negative reviews also are flowing in from groups ranging from the AFL-CIO to the American Medical Association and American Academy of Pediatrics.

The Black AIDS Institute, in a statement, noted the Republican plan would “basically kick poor people, old people and sick people under the bus” and ensure that “we cannot end the HIV/AIDS epidemic” because it would “take away health care from those who need it most.”

Republican supporters have only a narrow margin to pass their plan over the virtually unanimous objections of Democrats, including Virginia Reps. Robert C. Scott of Newport News and A. Donald McEachin of Henrico County, as well Virginia’s two senators, Mark R. Warner and Tim Kaine.

In the 435-member House, Republicans need 218 votes and can only lose 21 votes. And with 40 conservatives like Rep. Brat, that seems difficult.

In the 100-member Senate, Majority Leader Mitch McConnell could lose only two of the 52 members of the GOP Caucus. A 50-50 tie could be broken by the Republican Vice President Mike Pence. With at least six GOP senators expressing skepticism, Senate passage could be difficult.

The Republican plan is uniting congressional Democrats, who have been spending time in their districts collecting stories from people like Ms. Reivis.

“The Republican bill to repeal the ACA is fundamentally flawed,” Rep. Scott said in a statement Tuesday, “because it purports to cover pre-existing conditions without an individual requirement to purchase insurance,” which is now the case with ACA.

“In states that have tried this,” he stated “the markets have gone into total chaos. Furthermore, the tax credits proposed are likely to be insufficient for low-income working families.”

Sen. Tim Kaine also has added his voice to the opposition: “Republicans had seven years to pull together a plan, and now they insist on rushing to pass a bill without taking the time to analyze the cost and impact on the American people. I will not support a plan that dismantles Medicaid, raises costs for Virginia’s middle class families and seniors and defunds Planned Parenthood services for women while massively cutting taxes for the wealthy.”

Sen. Warner also is dismissive of the Republican plan, noting that Trumpcare cuts and caps Medicaid, “which means that a state like Virginia, which did not expand Medicaid, will get the short end of the stick.”

In his view, the House is rushing this bill through without saying how much it adds to the budget deficit.

Rep. McEachin also is scathing. “Republicans promised to replace the Affordable Care Act with, in President Trump’s words, ‘something great,’ ” he stated. “This bill is proof that those were hollow, meaningless promises. Instead of fixing what is wrong with the Affordable Care Act, Republicans are pushing a bill that helps fewer and increases costs.”