After facing a rocky start and chorus of naysayers who declared his health care law a failure, President Barack Obama on Tuesday celebrated a better-than-expected 7.1 million sign-ups for health coverage that he said should end the debate over whether the law should be repealed.

"The Affordable Care Act is here to stay," Obama declared in a feisty Rose Garden speech the day after the deadline for Americans to be enrolled for healthcare of face a fine.

Obama announced the 7 million threshold that once was seen as unattainable after a rocky rollout last fall — and the enrollment numbers could still climb. People who started applying but couldn't finish before the Monday midnight deadline have extra time, as do potential enrollees whose special circumstances delayed their signing up.

Meeting the deadline lets the uninsured avoid tax penalties for not having insurance, a major provision of the law aimed at reducing long-term costs, but people can sign up on the Healthcare.Gov website year round.

Administration officials said they were still compiling data beyond the 7.1 million sign-up figure, such as how many enrollees were previously uninsured and whether enough younger, healthy people signed up to offset the costs of covering older, sicker consumers. Those will be important metrics in determining the ultimate success of the healthcare overhaul.

Driving youth enrollment into the program has been a priority for the administration’s health care push, with Obama making an appearance on a comedian Zach Galifianakis’ satirical web series “Between Two Ferns” and the White House posting trendy memes promoting the law to Facebook and Twitter in hopes of catching the eyes of “young invincibles.”

The social media campaign came after a disastrous rollout of the Healthcare.gov site last fall, which failed to handle the traffic from the high number of visitors seeking insurance. In his speech today, Obama said after officials fixed these technical issues the law was working as he had hoped.

"The bottom line is this: Under this law, the share of Americans with insurance is up, and the growth of health care costs is down. And that's good for our middle class, and that's good for our fiscal future," the president said.

"As messy as it's been sometimes, as contentious as it's been sometimes, it's progress," Obama said.

At the same time, Obama lashed out at critics who still argue that the law should be repealed. "I don't get it," he said.

"Why are folks working so hard for people not to have health insurance? Why are they so mad about the idea of folks having health insurance? Many of the tall tales that have been told about this law have been debunked. There are still no death panels. Armageddon has not arrived. Instead, this law is helping millions of Americans, and in the coming years it will help millions more."

The law is expected to be at the center of some competitive mid-term national races across the country this fall, especially as Republicans hope to use Obamacare as a cudgel against Democratic successes at the polls in states where the Affordable Care Act is viewed unfavorably.

Michael Steel, spokesman for House Speaker John Boehner, R-Ohio, argued that the law was harming the American people.

"Every promise the president made has been broken: Health care costs are rising, not falling," Steel said Tuesday.

"Americans are losing the doctors and plans that they like — especially seniors suffering under President Obama's Medicare cuts. Small businesses are afraid to hire new workers, hobbling our economic growth. That's why we must replace this fundamentally-flawed law with patient-centered solutions that will actually lower health care costs and help create jobs."

Meanwhile, despite the administration meeting the 7 million mark, some questions remain about those who have sign up for healthcare.

"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."

Al Jazeera and wire services