WASHINGTON — Congress often waits for a new president to take office before it gets down to business. This year, Republicans will drop that custom in their dash to scrap the Affordable Care Act.
Within hours of the new Congress convening on Tuesday, the House plans to adopt a package of rules to clear the way for repealing the health care law and replacing it with as-yet-unspecified measures meant to help people obtain insurance coverage.
Then, in the week of Jan. 9, according to a likely timetable sketched out by Representative Greg Walden, Republican of Oregon, the House will vote on a budget blueprint, which is expected to call for the repeal of the Affordable Care Act.
Later, in the week starting Jan. 30, said Mr. Walden, incoming chairman of the House Energy and Commerce Committee, the panel will act on legislation to carry out what is in the blueprint. That bill would be the vehicle for repealing major provisions of the health care law, including the expansion of Medicaid.
Republicans in both houses of Congress have said that repealing the health law is a top priority for the first months of 2017. “The Obamacare repeal resolution will be the first item up,” said the Senate majority leader, Mitch McConnell, Republican of Kentucky.
President-elect Donald J. Trump has called the law an “absolute disaster,” and has said he is eager to sign a repeal bill like one vetoed by President Obama in early 2016.
Representative Nancy Pelosi of California, the House Democratic leader, said the rules devised by House Republicans were “their opening salvo” against a law that she said had been “successful in meeting its goals of reducing cost, increasing access and improving quality of care.”
In a last-ditch bid to save his signature legislative achievement, which has provided coverage to some 20 million Americans, Mr. Obama plans to visit a meeting of House and Senate Democrats on Wednesday to rally support for the law.
The Affordable Care Act, approved in 2010 without any Republican votes, provides tax credits to help people buy private insurance. It also allowed states to expand Medicaid eligibility, with the federal government paying most of the cost for new beneficiaries.
The law also saves hundreds of billions of dollars by reducing the growth of Medicare payments to hospitals, nursing homes, health maintenance organizations and other health care providers. Repealing the law would eliminate those savings and thus increase federal spending, the Congressional Budget Office says.
The proposed rules written by House Republicans allow lawmakers to raise a point of order against legislation that causes an increase in certain types of federal spending. But the rules give special protection to bills repealing or “reforming” the Affordable Care Act, even if such bills cause a temporary increase in spending.
Republicans worry that the Congressional Budget Office could count their plan for replacing the law as new spending, making it subject to challenge on the House floor. The exception being written into House rules would help them avoid that possibility.
Ms. Pelosi pointed to this provision as evidence that the health care law, as written, saves money. In their version of the rules, she said, “Republicans are admitting that repealing the Affordable Care Act will increase costs.”
The Congressional Budget Office said in 2015 that “repealing the A.C.A. would raise federal deficits by $137 billion over the 2016-2025 period” — not only because the government would spend more on Medicare, for older Americans, but also because it would collect less in taxes from high-income households.
The 2010 law, the budget office noted, increased the payroll tax rate for many high-income taxpayers and imposed a surtax on their net investment income. The law also imposed annual fees on health insurers and manufacturers of brand-name drugs and medical devices.
Republicans may want to hold on to some of the tax revenue and Medicare savings, to help offset the cost of their plan to replace the Affordable Care Act. They have been trying to devise that replacement, but do not have a consensus and may hold hearings to examine the options.
If Congress votes to repeal the health care law early in 2017, Republican leaders say, they may delay the effective date for several years, to avoid disrupting coverage for people who have recently gained it.