WASHINGTON — Republicans in the Senate and House of Representatives are aggressively pushing ahead with measures to repeal the Affordable Care Act despite the fact that they have no coherent alternative to replace it.

Health care industry analysts and trade associations have warned that repealing or gutting the law without an adequate substitute could create chaos.

Even the president-elect, Donald Trump, who has denounced the ACA in the strongest terms, has cautioned that congressional Republicans are risking a possible backlash by moving too quickly to ­dismantle it.

Nevertheless, vice president-elect Mike Pence and Speaker of the House Paul Ryan have expressed determination to begin the process of repeal immediately. The law was passed in 2010 without any support from Republicans.

The first step involved a budget resolution initiated in the Senate that would protect repeal legislation from a filibuster by Democrats. At presstime it was unclear whether Senate Republicans, who hold a 52 to 48 majority, would close ranks to pass the bill, which required only a simple majority.

According to The New York Times, the second stage of the repeal movement will require four committees — House Energy and Commerce; House Ways and Means; Senate Finance; and Senate Health, Education, Labor and Pensions — to quickly draft repeal legislation in the guise of a reconciliation bill. That bill is expected to contain clauses that will eliminate tax penalties on people who go without insurance; eliminate tens of billions of dollars in funding for states that have expanded Medicaid eligibility; and repeal subsidies for private health insurance coverage obtained through the public ­exchanges.

Republicans have said they will delay the effective date of the repeal bill to avoid disrupting insurance coverage and give themselves time to develop an alternative program. The delay could range from two to four years.

A member of Trump’s transition team, Rep. Chris Collins (R., N.Y.) told CNN there will be no changes to Obamacare in the next two years. “There’s not going to be any changes in 2017; there’s not going to be changes in 2018,” he said. “Those products have already been approved by the state insurance agencies, or for the 2018 time, are in negotiation right now. So we’re talking about new plans in 2019 or later that will be more affordable and let patients pick their ­doctors.”

The new president is also expected to play a role through executive actions. “We are working on a series of executive orders that the president-elect will put into effect to ensure that there is an orderly transition, during the period after we repeal Obamacare, to a market-based health care economy,” Pence told Congress without providing any details.

The Wall Street Journal cites health care analysts who suggest Trump could cripple the insurance exchanges created by the ACA in a number of ways. One would be to eliminate the requirement for individuals to buy health coverage or pay a penalty.

Doing so could trigger an exodus of insurers from the ACA’s insurance exchanges, since without the mandate, sign-ups are expected to be dominated by older consumers with more ailments who are unprofitable to payers.

Additionally, Trump could drop the appeal of a House lawsuit that challenges funding for subsidies to about 7 million exchange consumers. Finally, he could halt outreach efforts during the 11 days of the sign-up period that will remain once he takes office.

While Republicans continued to denounce Obamacare as a failure and devise tactics to ensure that blame attaches to the Democrats who passed it, the White House reported that, as of mid-December, a record 6.4 million people had signed up for health insurance through the 2017 ACA program. Approximately 9% of Americans now lack health insurance, less than half the rate before the ACA was enacted.

Neither Trump nor Republican congressional leaders have provided more than sketchy suggestions for what might replace the ACA. Pence has said that replacement legislation will probably encourage more use of personal health savings accounts and also remove barriers to selling insurance policies across state lines, an idea touted by Trump during the campaign. Small businesses will probably be encouraged to buy insurance through association health plans sponsored by business and professional organizations. Consumers may receive some kind of subsidy or tax credit to help defray the cost of their insurance ­premiums.