Mr. Brindisi said the repeal bill, the American Health Care Act, would have had devastating effects on the district that Ms. Tenney represents in upstate New York, harming hospitals that are important to the local economy and diminishing access to opioid treatment.
But in an interview last week, Ms. Tenney, a former state assemblywoman who is in her first term, showed no sign of regret.
“The real issue is, how are we going to make health care affordable again?” she said. “We polled ‘repeal and replace’ twice,” she added. “People want Obamacare repealed in the majority in my district.”
On one level, the passage of the House repeal bill was a political achievement for Republican lawmakers; after years of campaign promises, they could tell their political base that they had done what they had pledged to do, even if the Senate stumbled once the baton was handed over to that chamber.
But viewed another way, the House repeal bill amounted to a political gift to Democrats. Opponents said its enactment would have left people with pre-existing medical conditions unable to afford health coverage and would have resulted in health plans that omit benefits that are currently required, like maternity care and mental health services. Republicans said Democrats’ claims were exaggerated, if not false. But the bill never became law, and supporters have no way of getting real-world evidence to refute them.
All told, the House bill would have increased the number of people without health insurance by 14 million this year and by 23 million in 2026, the Congressional Budget Office estimated.
A year ago, Democrats warned that Republicans were practically begging voters to unseat them. When the repeal bill narrowly passed the House, Democratic lawmakers serenaded their Republican colleagues with, “Na na na na, na na na na, hey hey hey, goodbye!”
Beyond the House repeal bill, Democrats have also developed a broader argument that Republicans have inflicted damage on health insurance markets, partly because of actions taken by the Trump administration to undermine the Affordable Care Act. Just this week, they gained an assist from an unlikely figure: Tom Price, Mr. Trump’s former secretary of health and human services, who said that ending the requirement that most people have coverage, known as the individual mandate, would increase costs for people buying insurance.
Helping the Democrats, polls have shown that the Affordable Care Act has gained in popularity since the 2016 elections. In an NBC News/Wall Street Journal poll conducted last month, Democrats had an 18-percentage-point edge when people were asked which party they thought would do a better job dealing with health care.
To mark the anniversary of House passage, health care advocates are holding events around the country this week. On Friday, a coalition called Save My Care plans to air a television commercial that reminds viewers about the House bill and concludes with the narrator saying, “We won’t forget.”
Representative Tom Cole of Oklahoma, a former chairman of the House Republicans’ campaign arm, cast doubt on how much of an effect the repeal bill would have in midterm races.
“I don’t think talking about a bill that didn’t happen is particularly effective,” he said. “People punish you for things that you do successfully, not for things that never happen just because you cast a vote.”
Mr. Cole suggested that a more significant risk stemmed from Republican voters who are disappointed that their party’s lawmakers ultimately failed to repeal the health law despite years of promises. “It’s more a matter of deflating our base than enraging the other side, because they’re already pretty enraged and energetic anyway,” he said.
Then there is the question of how much health care will remain a prominent issue when last year’s repeal effort is an increasingly distant memory.
“My fear is that there’s all this salacious stuff — there’s all this focus on Russia and Stormy Daniels and Michael Cohen,” said Laurel Smith, 57, a health care activist in New Jersey whose congressman, Tom MacArthur, played a pivotal role in passing the House repeal bill. “It’s easy to get distracted.”
Ms. Smith said she had previously voted for Mr. MacArthur, a Republican, but now backs his Democratic challenger, Andy Kim. Ms. Smith’s 27-year-old son, who has a chronic and uncurable disease, has been volunteering for Mr. Kim’s campaign.
Mr. Kim, a former National Security Council staff member in the Obama White House, said he wants every voter to know about Mr. MacArthur’s role, which landed him a speaking slot at the Rose Garden ceremony.
“He wasn’t just a yes vote,” Mr. Kim said. “He’s got his name on it.”
Mr. MacArthur said he was not worried.
“The reality is I didn’t come here to be a potted plant,” he said. “I came here to work on problems facing the American people, and health care costs are hurting my constituents.”
But that Rose Garden ceremony remains a touchstone.
Elissa Slotkin said she was contemplating a run for Congress when she saw her congressman, Mike Bishop of Michigan, at that Rose Garden celebration.
“He was smiling and beaming and proud and thrilled,” she recalled. “I turned to my husband and said, ‘You do not get to do this. You don’t get to ignore the public and vote against their interests and keep your job.’ ”
Ms. Slotkin, a former senior official in the Defense Department, jumped in. She is seen by the House Democrats’ campaign arm as a formidable challenger.
Mr. Bishop bristled at his critics.
“In order to win this, the Democrats have infused fear and panic, and they have done so by misrepresenting the truth,” he said. “If you need to do that to win, then count me out, because I would never do that.”