The federal government spends $7 billion a year on the subsidies. The money goes directly to insurers, which are required to provide discounts to low-income people regardless of whether the companies are reimbursed by the government.

House Republican leaders had refused to provide money for the subsidies in their bill to repeal the Affordable Care Act, which was approved by the House last month. The White House balked at including the money in a sprawling spending bill to finance the government through September. And Mr. Trump has threatened to withhold the subsidies as a way to force Democrats to negotiate with him on a replacement for the 2010 health care law.

But Mr. Brady said the payments were needed to help consumers.

“Obamacare’s design flaws were not the fault of the American people,” Mr. Brady said. “The people now trapped in Obamacare did what the government mandated them to do — they complied with the law. They should not be left out to dry.”

House Republicans filed a lawsuit in 2014 asserting that the Obama administration was paying the subsidies illegally because Congress had never appropriated money for them, and a Federal District Court judge agreed last year. She ordered a halt to the payments, but suspended her order to allow the government to appeal. That appeal is still in progress, though it is unclear how far the Trump administration will take the fight.

At separate hearings of the House Ways and Means and Senate Finance Committees on Thursday, Tom Price, the secretary of health and human services, got a tongue-lashing from Democrats who said he and Mr. Trump were pursuing policies that could deprive millions of Americans of health care and coverage.

Representative Suzan DelBene, Democrat of Washington, said the administration was causing “chaos, confusion and instability in the market.”

In response to similar criticism from senators, Mr. Price said: “Nobody is interested in sabotaging the system. Nobody is cheering the challenges that we have in the system.”