President Obama faces a dual challenge in the months ahead: Convince uninsured Americans to sign up for Obamacare and keep worried Democrats on board as the administration enacts his health care overhaul.

The rollout of the Obamacare health exchanges Oct. 1 touched off a high-stakes messaging battle over the president's signature legislative achievement, a clash with enormous repercussions for the 2014 midterm elections.

Playing an expectations game, Obama’s surrogates have openly argued that it could take months, if not years, for Americans to fully appreciate the impact of a law that polls show has been greeted with confusion and skepticism.

Obama’s political allies don’t have time to spare, however.

“To a certain extent, we sink or swim on how the public views the law,” conceded a top Senate aide to a centrist Democrat up for re-election in 2014. “There’s a lot of work left to do. The White House isn’t the only one with skin in the game.”

As Obama trumpeted the unveiling of the online marketplaces, much of the attention in Washington turned to problems with the technology undergirding the sweeping new law. Computer glitches could harden perceptions against the president’s health reforms, especially since new enrollees won’t receive Obamacare benefits until next January at the earliest.

The federal government shutdown and an even larger looming fight over raising the nation’s debt limit are diverting attention just when the administration hoped to sell the public on the health law.

After years of promising expanded health care coverage at affordable rates, the president has no choice but to trumpet Obamacare in the face of so many distractions and potential pitfalls.

How to define a successful rollout, though, is in the eye of the beholder.

Over the next six months, the administration is aiming to enroll seven million people in Obamacare. It’s a figure that critics say doesn’t give a full portrait of whether the law meets lofty promises about fundamentally improving health services for Americans.

“More than 6 million people lost health insurance [since the height of the recession],” said Dennis Smith, former health secretary under Wisconsin Republican Gov. Scott Walker. “The White House’s goal is only a net increase of 1 million. And that’s not just the previously uninsured, it includes people substituting one coverage plan for another.

“The 7 million number doesn’t begin to accurately tell us whether it worked,” Smith added. “You have to determine who they are; what their previous circumstances were like.”

Strategists say the administration must not only enroll people in Obamacare, but also prove their lives have been improved by the decision.

To insulate Democrats from political blowback, the White House’s Obamacare mission is three-fold: Convincing Americans that they won’t experience “rate shock” under the law, that health care costs are going down and, most importantly, that a policy change bearing the president’s name isn’t a jobs-killer.

“Redefining it as affordable care has to be task one,” New York-based Democratic strategist Hank Sheinkopf said. “Argue that ‘Washington is nuts, here is the part of the law that will help you.’ The administration has to prove it works — then there’s no more discussion.”

Making the sales job more difficult is the friendly fire raining down on Democrats.

Labor leaders, who lobbied hard for passage of the law, are now calling for changes to Obamacare, saying the president should approve revisions that would give union members subsidies to help offset taxes on their generous health care plans.

Despite personally meeting with union leaders, the president was unable to quiet their concerns, potentially sapping support for the law at a time when Obama needs unalloyed enthusiasm from his most loyal backers.

Yet Obama is painting an increasingly glowing picture of his health plan, saying that Americans will embrace it as they have Social Security and Medicare.

“A few years from now ... there are going to be a whole bunch of folks who say, ‘Yes, I always thought this provision was excellent,’ ” Obama predicted, saying he even expected Republicans to come around. “You watch. It will not be called Obamacare.”

But before Obama's legacy is decided, Democratic lawmakers facing elections next year will face a verdict on Obamacare that could make or break their careers.

“’A few years from now’ isn’t all that comforting,” said the Democratic Senate aide. “That doesn’t do us a whole lot of good next November.”