“They’ve got nothing. They’ve never had anything,” said Representative Zoe Lofgren, a California Democrat who helped pass the law, officially called the Affordable Care Act. “It’s been 15 years of blowing smoke.”

The inability of Republicans to produce a comprehensive proposal, despite dozens of failed attempts in Congress to “repeal and replace” Obamacare, further complicates the effort to address the expiring subsidies. It also puts Republicans in a potentially vulnerable political position heading into next year’s midterm elections, as Democrats have used the shutdown to highlight their defense of Obamacare, which polls consistently show is popular.

“Republicans have a long list of ideas,” House Speaker Mike Johnson said on Oct. 27, holding up reports that his fellow House Republicans have produced on health care in the past. He announced that House majority leader Steve Scalise and key Republican committee chairs were working on “grabbing the best ideas that we’ve had for years, to put it on paper and make it work.”

Trump has recently said he wants to scrap the entire Obamacare system and give the money from the tax credits — which often go directly to health insurance companies to help pay for an enrollee’s premiums — to Americans in some sort of health savings accounts.

“They’re going to go out and buy their own health care, and we’re going to forget this Obamacare madness,” Trump said on Wednesday night as he signed the legislation reopening the government.

White House spokesperson Kush Desai declined to provide details about the plan but said, “Democrats’ push to maintain these high prices by giving more money to insurance companies is not a real solution.”

“The president has instead focused on lowering prescription drug costs by hammering out deals with pharmaceutical companies, as well as taking on waste, fraud, and abuse in the system to deliver results for patients, and will continue to deliver policy solutions that lower costs in the health care market for the American people,” Desai said.

After failing for his entire first term to release an alternative to Obamacare that he repeatedly said was close, Trump declared, toward the end of last year’s presidential campaign, he had “concepts of a plan.” On Thursday, Politico quoted someone familiar with White House discussions on the expiring tax credits as saying the work was in the “early ideation phase.”

President Trump’s press secretary, Kayleigh McEnany, gave us a heavy book that she described as the president’s health care plan. It was filled with executive orders and congressional initiatives, but no comprehensive healthcare plan. https://t.co/Mn6HRAOwHL pic.twitter.com/WmsoRQP2WJ

— 60 Minutes (@60Minutes) October 26, 2020

“What problem are we trying to solve?” asked Cynthia Cox, an expert on the Affordable Care Act at KFF, an independent health policy research, polling, and news organization. “If you’re just going to use all the same dollars that went to the enhanced premium tax credits and try to put it into some other form, is that a solution in search of a problem?”

Republicans point out that the Affordable Care Act has failed to live up to Obama’s initial promise to significantly reduce family health care costs.

But the ACA has slowed the growth of those expenses while significantly increasing the percentage of Americans with health insurance. People are able to get government subsidies in the form of tax credits to pay premiums for private health insurance purchased through the ACA, which offers a standard level of coverage, including for pre-existing conditions, pregnancy, and prescription drugs.

Initially, the tax credits were only available to households with annual incomes no more than four times the poverty level. (In 2025, that meant a single person couldn’t have more than $62,600 in income, and a household of four no more than $128,600).

But during the COVID-19 pandemic, Democrats in Congress temporarily expanded the tax credits and allowed wealthier earners to receive them. KFF said that led ACA enrollment to more than double to over 24 million people.

The expiration of those enhanced tax credits, coming when health care costs are rising due to inflation, industry consolidation, increased demand for new specialty drugs, and other factors, would result in an average jump in ACA premiums of more than 75 percent, according to KFF. Since open enrollment for next year began several weeks ago, consumers have been hit with sticker shock, and many won’t be able to afford the new price.

Nearly all congressional Democrats refused for weeks to approve a short-term government funding bill that did not include an extension of the enhanced subsidies. But with Republicans holding firm, eight Senate Democrats agreed to provide the necessary votes largely in exchange for a promise from Senate majority leader John Thune to hold a vote in December on a Democratic bill to extend the subsidies.

House Republican leaders have not promised any such vote. But Thune was optimistic about a deal if Democrats are open to changes in Obamacare.

“Obviously, what we have today isn’t working,” Thune told reporters. “So if there is a willingness on the part of Democrats to work with Republicans to deal with the unaffordability of Obamacare in its current form, then there might be an opportunity to do something bipartisan.”

Some Senate Republicans have indicated they would support an extension, with reforms. Maine Senator Susan Collins said she wants “some cap on income so that very wealthy individuals are not able to receive taxpayer-funded tax credits.”

But other Republicans have echoed Trump’s demand for a major overhaul.

“We’ve got to figure out how to drive the cost of health care down, not just keep subsidizing more and more people,” said Florida Senator Rick Scott, who once ran a large health care company. He and other Republicans have embraced Trump’s idea to send the ACA subsidy money directly to Americans, allowing them to buy their own health insurance.

Such a change could torpedo Obamacare, according to Cox.

“It would cause adverse selection to the point that it could actually crash the entire ACA market,” she said, referring to the practice in which people with greater medical needs are more likely to buy coverage. “Only the sickest people would be left in the market. No insurers would want to participate. It would lead to what’s called a death spiral.”

Representative Bill Keating, a Bourne Democrat, said that’s the goal of Trump and the Republicans, noting changes such as a proposed reduction in the open enrollment period to 45 days from 90 days.

“Trump has made it clear: piece by piece, he wants to destroy the Affordable Care Act,” Keating said. “This is an important way to do it.”

House and Senate Democratic leaders have promised to fight to extend the subsidies.

”We will be working hard today, tomorrow, and throughout the balance of this year to make sure that those Affordable Care Act tax credits are extended,“ House Democratic leader Hakeem Jeffries said before Wednesday’s government funding vote. He called for extending the enhanced subsidies for three years.

Senator Bill Cassidy, a Louisiana Republican and a physician, is attempting to thread the needle on an overhaul that would satisfy both Trump and Democrats. He has proposed shifting the enhanced subsidy money to “pre-funded flexible spending accounts” while leaving the rest of Obamacare alone.

“We empower patients to shop, to find the best deal for their dollar,” Cassidy said in a lengthy presentation on the Senate floor on Nov. 9. “That drives competition and that lowers cost.”

But that might not go far enough for Trump, who has been searching for an alternative to Obamacare for years.

“The insurance will be better. It’ll cost less. Everybody’s going to be happy,” Trump told Fox News on Nov. 10, of his vague plan to send all the funding directly to Americans to buy coverage on their own. “Call it Trumpcare. Call it whatever you want to call it. But anything but Obamacare.”

Jim Puzzanghera can be reached at jim.puzzanghera@globe.com. Follow him @JimPuzzanghera.