WASHINGTON — Driven by a last-minute flood of enrollments, particularly in California, sign-ups for health insurance through the Affordable Care Act's online marketplaces hit 8 million, President Obama announced Thursday.
The total exceeded the initial forecast by 1 million people and capped a notable comeback after a disastrous debut last fall gave rise to predictions the law would collapse in its maiden year.
The health law, often called Obamacare, instead has brought about the largest increase in insurance coverage in the United States in the half a century since Medicare and Medicaid were created.
"This thing is working," Obama said from the White House briefing room.
He took repeated jabs at his Republican critics who continue to pledge to roll back the law, showing a new willingness to go on the political offensive on the subject.
"The repeal debate is, and should be, over," he declared. "We've been having a political fight about this for five years. We need to move on to something else."
The final surge of enrollments came heavily from California, which signed up more than 200,000 consumers in the last two weeks, state officials said Thursday. Those late arrivals brought the state's total to nearly 1.4 million people, far ahead of all other states.
Although the numbers will continue to fluctuate throughout the year as some people obtain insurance and others drop it, Thursday's announcement marked a significant milestone as the first open enrollment period ended for most people.
Enrollment initially was set to end March 31, but the administration and several states gave additional time to people who said they had started the process by that date but hadn't finished. That grace period expired April 15 for the federal marketplace, which is used in 36 states. Some states that operate their own online exchanges, including California, adopted the same deadline, although others have allowed more time.
Estimates of the total increase in insurance coverage nationally are still preliminary, but new Gallup survey data released this week suggest that as many as 12 million previously uninsured Americans have gained coverage. That number includes people who signed up on the new marketplaces, but also those who acquired insurance through the law's expansion of Medicaid, through their employers or directly from insurers.
Just 12.9% of adults nationally lacked coverage in the first half of April, initial data from the Gallup-Healthways Well-Being Index indicate. That's down from 18% in the third quarter of 2013, just before the new marketplaces opened for business.
"It's a remarkable turnaround," said Gerald Kominski, director of the UCLA Center for Health Policy Research. "Who would have thought after such a horrendous rollout of the federal website that the government's goals could have been not just met but exceeded?"
Despite that success, substantial obstacles still confront the health law.
One of the top worries for the administration is the risk that big rate increases next year could drive away consumers. Senior administration officials, including the president, met Thursday at the White House with state insurance regulators and insurance industry executives to press them to hold down premiums.
In California, state leaders are also wrestling with ways to ensure that marketplace plans offer consumers access to an adequate number of doctors and hospitals. Some consumers have complained that plans being sold on Covered California have overly narrow networks, making care difficult to obtain.
Steve Pickett, an Oakland resident who signed up for a platinum plan from Blue Shield of California with the help of a generous government subsidy, discovered last week that two of the orthopedic surgeons listed as being in network would not take his insurance. "I felt totally blindsided," he said.
Such stories are grist for Republicans who continue to hammer at the law ahead of this year's midterm elections.
Although surveys show that many Americans have grown tired of the healthcare debate, that is generally not true among conservative Republicans. Many of them have come to see the law as a symbol of all they dislike about Obama, and attacking it has proved an effective way for GOP candidates to mobilize their voters. Party strategists believe that continued anger over the law will help Republicans take control of the Senate in this fall's elections.
But the unexpected success of the new insurance marketplaces has shifted the political landscape, all but assuring the end of the long GOP campaign to repeal the law. Across the country, Republican lawmakers and candidates increasingly are being confronted by constituents asking them why they want to take away new protections created by the law, including guaranteed health coverage and discounted drug coverage for seniors on Medicare.
Obama, in his remarks Thursday, sought to stoke that concern and chided the GOP for continuing its campaign for repeal.
Republicans are "going through, you know, the stages of grief" regarding Obamacare's success, he said, "anger and denial and all that stuff."
"If the Republicans want to spend the entire next six months or year talking about repealing a bill that provides millions of people health insurance, without providing any meaningful alternative," he added, "that's their prerogative."
He also offered advice to his party's candidates, some of whom have notably distanced themselves from the law. Citing a woman he met earlier in the week in Pennsylvania whose family had benefited from the law, he said that "Democrats should forcefully defend and be proud of the fact that millions of people" like her had gotten help.
"I don't think we should apologize for it, and I don't think we should be defensive about it. I think there is a strong, good, right story to tell."
Republicans made clear they had no interest in dropping their quest to repeal the law.
"The repeal debate is far from over," Sen. Ted Cruz (R-Texas) said in a Twitter message.
House Majority Leader Eric Cantor (R-Va.) demanded to know "how many Obamacare enrollees were previously uninsured" — one of several questions Republican leaders have raised in recent days to challenge the administration's figures.
As the political debate wears on, the future of the law may be determined more by how consumers act. State and industry officials estimate that about 10% to 20% of new customers on the marketplaces have yet to pay their initial premiums, which for some consumers may not yet be due.
Some insurance executives worry about significant attrition as consumers struggle with premiums or grow unhappy with high deductibles or other limits on their policies.
"Is there sufficient capacity of hospitals and doctors in the places where demand will increase? We don't really know that yet," said Glenn Melnick, a health policy professor at USC. "Now people have this insurance card and they're asking, 'What does it get me?'"
Many insurers nonetheless remain committed to making the marketplaces work. And emerging data on the new consumers suggest that, although the pool is older than some had hoped, a significant number of young people have signed up.
Thursday, the White House announced that 28% of enrollees on the federal exchange were between 18 and 34, a coveted age group that is typically healthiest. California officials reported a similar percentage of young enrollees.
California said it continued to make gains among Latinos after a slow start. In the first half of April, Latinos accounted for 39% of enrollees, compared with 18% of those signing up in the first three months ending in December.
Peter Lee, executive director of Covered California, said "the people enrolling kept getting younger and more diverse."
Also Thursday, executives with UnitedHealth Group, the country's largest insurer, said on a call with investors that the company is looking to expand into more Affordable Care Act marketplaces next year.
Levey reported from Washington, Terhune from Los Angeles.