It could happen with a sustained surge in consumer demand and a foolproof website. But they're not seeing it yet, and time is running out.
The Department of Health and Human Services said more than 940,000 people signed up during February for private coverage under President Barack Obama's health care law, bringing total sign-ups to 4.2 million.
With open enrolment ending March 31, that means to meet the goal, another 1.8 million people would have to sign up during the month, an average of about 60,000 a day.
That's way above the daily averages for January and February, which have ranged between 33,000 and 34,000. The math seems to be going against the administration.
If the target isn't met, the immediate fallout will be political. Republicans will say it proves their point that Obama's signature project never had the public's support. Backers of the law will have to work harder to smooth out some of its problems and convince Americans to take a second look.
Administration officials expect the pace to pick up as procrastinators are forced to act. There are no plans to extend the March 31 deadline, they emphasize. The big question is whether that will be enough to make up for the technical troubles that paralyzed HealthCare.gov much of last fall and the continuing challenges for several state-sponsored websites.
"Given what we know about past enrolment patterns for health care, we expect that even more (people) will sign up as we approach the March 31 deadline," said HHS Secretary Kathleen Sebelius.
Julie Bataille, communications director for the health care rollout, said she expects millions more to sign up — but she wouldn't commit to a number by March 31.
The goal of 6 million sign-ups is itself a lower bar than was originally set. The Congressional Budget Office scaled back its original target of 7 million because of the federal website's computer problems. HealthCare.gov serves 36 states, while 14 states and Washington, D.C., are running their own sites.
The 943,000 enrolled in February fell short of the target of 1.27 million that HHS had initially set for the month.
And the cumulative total of 4.2 million sign-ups is just three-fourths of the 5.65 million that HHS originally projected would sign up by the end of February. Those estimates are from a Sept. 5, 2013 departmental memo.
The numbers released Tuesday still don't say how many of those signing up were previously uninsured, which is the ultimate test of Obama's health care overhaul.
And they don't say how many consumers have sealed the deal by paying their premiums.
Health care industry consultant Robert Laszewski said that undercuts his confidence in the numbers.
"They are still reporting numbers that are inflated," he said.
Separately, a Gallup survey released Monday found that the share of Americans without health insurance has been going down so far this year, albeit modestly.
Enrolling for health care under Obama's law is still nowhere near as simple as shopping online. Bataille said consumers make an average of six visits to HealthCare.gov, spending 20 to 30 minutes per visit.
Among the highlights of Tuesday's federal report:
— Young adults seemed to be showing a little more interest in signing up. Of those signing up in February, 27 per cent were between the ages of 18-34. Their premiums are needed to help defray the cost of caring for older generations. Independent analysts have said the mix should be 40 per cent young adults.
But people 55-64 are the leading age group among those signing up, cumulatively accounting for 30 per cent of total enrolment.
—More than four out of five who have enrolled thus far were eligible for tax credits to help offset the cost of premiums, and in some cases also to reduce their deductibles and copayments.
—Sixty-three per cent of those signing up picked a mid-range silver plan.
—Fifty-five per cent of those signing up are women, and 45 per cent are men. "Enrollment among women remains particularly strong," Sebelius said.
An AP analysis of state-by-state enrolment numbers showed that 13 states are running ahead of their enrolment targets. Virginia, with a new Democratic governor who supports the health care law, was the latest addition to that list. Six of the top-performing states are led by Republican governors: Florida, Idaho, Maine, Michigan, North Carolina, and Wisconsin.
Some states that have run into trouble have reduced their enrolment goals. But based on the original HHS enrolment targets, the five at the bottom are Massachusetts, Washington, D.C, Oregon, New Mexico, and Nevada.
Associated Press writer Kevin Vineys contributed to this report.