Obamacare has been defined by delays, broken promises and growing disillusionment with President Obama's signature domestic achievement.

Yet for all the problems and political headaches caused by the health care law, the real test for the White House begins on Jan. 1.

That's when Americans for the first time will visit their doctors with expectations of being enrolled in new health plans. And if the rocky last few months were any indication, that's hardly guaranteed.

The Obamacare rollout was embarrassing enough, but in terms of real-world impact, the implications are still somewhat abstract for much of the public. Now the uninsured and those with significantly altered medical coverage will have the chance to see whether the goods match Obama’s sales pitch.

Democrats, not surprisingly, are on edge.

“It seems pretty basic, this idea of getting what you’ve paid for — or thinking you’ve paid for,” one Democratic strategist closely aligned with the White House said. “It seems like things have gotten somewhat better. Now we’ll know for sure — and so will voters.”

The White House has trumpeted technical improvements to the problem-ridden healthcare.gov website, but the greater concern is whether insurers can lay the foundation for a sweeping policy change in which the goalposts move on a seemingly daily basis.

Obama and his top surrogates predicted that 3.5 million people would enroll in Obamacare plans by the end of the year, building momentum for a dramatic overhaul to how Americans receive medical coverage.

Instead, just a fraction of that estimate will have signed up for Obamacare, with an even smaller percentage of people having paid for new insurance coverage.

Insurers are growing increasingly agitated with delays they say undermine their ability to implement the core provisions of the Affordable Care Act.

“There’s this general feeling of, ‘What’s next,’ ” said one senior insurance official of the many delays. “The rules change on a daily basis. And we’re the ones who are left holding the bag every time [the administration] goes in a different direction.”

The most drastic change was unveiled last week when the administration announced that millions of Americans whose health plans were canceled under Obamacare would not be subject to the individual mandate. Rather than paying a fine for not obtaining health insurance by the end of March, those with canceled policies could instead sign up for so-called hardship exemptions.

Obama had requested that insurers extend canceled plans for another year, but many of the nation’s largest insurance companies resisted the White House’s last-second appeal.

Even after pushing back for a week the deadline to receive Obamacare coverage effective Jan. 1, the administration again secretly extended the cutoff date to Christmas Eve.

That move followed a slew of delays as the administration put off until 2014 the employer mandate, the cap on out-of-pocket medical costs and major Obamacare requirements for small businesses.

Despite White House claims that “back-end” issues on healthcare.gov have been largely fixed, insurers are still voicing concerns about receiving enrollment information for those who have signed up for new health plans. For months, insurers struggled to access information sent from healthcare.gov about new enrollees.

“Consumers should still check with their issuer to confirm the date their first month's premium is due,” Julie Bataille, a spokeswoman for the Centers for Medicare and Medicaid Services, warned on Monday.

In other words, come Jan. 1, some will mistakenly assume they have new health care coverage.

The administration has responded with a handful of tweaks they say will ensure coverage for those who fall through the cracks.

Under new administrative rules, consumers who attempt to sign up for Obamacare but run into technical issues will “qualify for a special enrollment period.” It’s not yet clear how insurers will respond to the directive.

America's Health Insurance Plans, the industry’s top trade group, also said last week they would extend their deadline for consumers to pay premiums for their new insurance plans until Jan. 10.

What Republicans frame as symptoms of a poorly conceived law, Obama is portraying as the type of flexibility needed to address correctable glitches.

“[What] we are constantly doing is looking: ‘Is this working the way it's supposed to?’ And if there are adjustments that can be made to smooth out the transition, we should make them,” Obama said during his last news conference of 2013. “But they don’t go to the core of the law.”

Some in the insurance industry say, however, the collection of “adjustments” is far more than tinkering around the margins of the law.

“It’s simple,” said the insurance executive. “With all these changes, it’s a confidence issue. How do you come up with accurate prices for each plan? There was so much planning for what they told us to do and now, to some degree, it’s like they’re saying, ‘Never mind, just kidding.’ ”