WASHINGTON (AP) -- A surge of eleventh-hour enrollments has improved the outlook for President Barack Obama's health care law, with more people signing up overall and a much-needed spark of interest among young adults.
Nonetheless, Obama's announcement Thursday that 8 million have signed up for subsidized private insurance, and that 35 percent of them are younger than 35, is just a peek at what might be going on with the nation's newest social program.
Still to be announced is what share of those enrolled were previously uninsured - the true test of Obama's Affordable Care Act - and how many actually secured coverage by paying their first month's premiums.
"This thing is working," a confident Obama said of his signature domestic achievement. The days of website woes and canceled policies seemed far behind.
State-by-state statistics, expected as early as next week, will provide a much fuller picture.
A key question is how many of those signed up were young adults, ages 18-34. They're the health care overhaul's most coveted demographic because they're healthier than older adults and their premiums can help cross-subsidize care for the sick. That would help hold down future premium increases.
According to the nonpartisan Kaiser Family Foundation, young adults 18-34 represent about 40 percent of the people eligible to buy coverage in the health care law's new insurance markets. The White House says that group now accounts for 28 percent of those who have picked a plan in states where the federal government is running the insurance exchanges.
Not perfect, but not bad either, said Larry Levitt, an insurance expert with Kaiser.
"Enrollment among young adults ended up lower than their share of the target population but sufficient to keep the market stable in the vast majority of the country," he said.
The nonpartisan Congressional Budget Office is forecasting only a slight average increase in premiums for 2015. Some private insurance experts expect big differences around the country, predicting that insurers will seek noticeably higher premiums, around 6 percent to 8 percent on average.
Republicans were having none of Obama's celebration. A statement from the office of Senate GOP leader Mitch McConnell of Kentucky said he remains committed to repealing the law and replacing it.
The president appeared in the White House briefing room to trumpet the new figures, which beat initial projections by 1 million people
Following the disastrous rollout of the insurance exchanges in October, when HealthCare.gov was virtually unusable, Democrats have been hoping that higher-than-expected results could help their candidates reclaim the political high ground ahead of the midterm elections.
Seven months out from Election Day, they're seeking to turn the page on the law's flawed debut - a strategy underscored last week when Obama announced that Health and Human Services Secretary Kathleen Sebelius, who became the face of the rollout failure, was stepping down.
Polling shows the law remains unpopular in much of the country, yet most Americans say they don't expect it to be entirely repealed, but changed in some way.
With the insurance markets looking increasingly viable, Obama and Democrats were hoping to move the political debate away from repeal and toward efforts to fix lingering issues.
Republicans have been reluctant to pursue fixes for fear of tacitly embracing the overall law. Obama said that it's "absolutely possible" to make improvements but that it would require a change of attitude from Republicans.