President Barack Obama's national healthcare program signed up more than 7 million people by the last day of March, the White House said on Tuesday, notching a rare victory after a months-long, glitch-filled rollout of the law.
Obama is scheduled to make a statement about the Affordable Care Act, popularly known as Obamacare, at 4:15 p.m. EDT (2015 GMT) in the White House.
His remarks could be the start of a victory lap for the administration, which suffered from the botched unveiling of the program's primary website, HealthCare.gov, and wavering support from Americans years after the U.S. Congress passed the healthcare law over Republican objections.
"With the remarkable surge in enrollment, 7,041,000 people signed up for health insurance before the midnight deadline yesterday and that doesn't count the last day surge in signups in more than a dozen states that run their own marketplaces," White House spokesman Jay Carney told reporters.
Experts had predicted a last-minute surge. The number represented what the White House has called a comeback story that could boost Democrats in the November congressional elections.
Obama's party is seeking to hold on to control of the U.S. Senate and minimize losses in the Republican-controlled House of Representatives, but the problems with Obamacare have complicated congressional races and handed Republicans a key talking point for skeptical constituents.
After a White House meeting with Obama, House Democratic leader Nancy Pelosi told reporters her members were not running away from the issue as they approached the elections.
Monday's deadline for initial enrollment in the program came after a surge in registrations despite the return of technical problems, including a longer-than-expected maintenance session, although nothing as serious as the issues that beset the website's launch in October.
The site on Tuesday announced that open enrollment for Obamacare had closed, but people whose applications were thwarted by technical problems would be given a chance to finish their registration.
By last week, more than 6 million people had signed up for private health coverage through the new Obamacare insurance markets, surpassing a target set after the disastrous rollout called the enrollment process into question.
Despite the figures, some questions about those who had signed up lingered.
"We still have a lot to learn about what underlies those numbers in terms of who signed up and how many were newly insured people versus switching from other coverage," said Karen Pollitz, a senior fellow at the Kaiser Family Foundation.
"We have more to see ... about how many of them actually completed enrollment and how much coverage expansion was accomplished."
The healthcare law, one of Obama's key promises as a presidential candidate in 2008, was intended to expand access to healthcare coverage for millions of uninsured Americans, so having enrollment figures that reflect newly insured people is critical to the program's success.
Having a robust percentage of healthy young people to offset older enrollees is also important. A breakdown was not yet available, Carney said, but the demographic mix would be sufficient to ensure that the health market places that form the cornerstone of the law would function smoothly.
Republicans pointed to several outstanding questions about the numbers, including how many of the enrollees had seen their plans canceled because of the new law; how many people saw their premiums go down; and how many people who selected plans actually completed the process and paid their premiums.
"We don't know of course, exactly what they have signed up for, we don't know how many have paid," Senate Republican leader Mitch McConnell told reporters on Capitol Hill, referring to the enrollees in the program.
"What we do know is that all across the country our constituents are having an unpleasant interaction with Obamacare. Whether they can sign up for a policy or not, they are discovering, of course, higher premiums, a higher deductible."
The future of Obamacare is one of the top issues in the November elections. House Speaker John Boehner on Monday pledged once again to repeal the program.