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The federal health care overhaul was central to President Obama's two campaigns for the White House, and has been the defining achievement -- for better or worse -- of his presidency.

But one of the architects of ObamaCare, in a heated interview on "Fox News Sunday," argued that the reason young people are not signing up in droves for coverage under the law is the administration hasn't promoted it.

Ezekiel Emanuel, a former health adviser to the president (and the brother of former White House Chief of Staff Rahm Emanuel), argued the administration has been too caught up with fixing HealthCare.gov to give the law the proper promotional push.

"No one has launched a big PR campaign to get these people signed up because of the problems with the federal website," he told "Fox News Sunday." "We are about to launch a big PR campaign, and that, I think, is going to persuade a lot of people to sign up."

He noted the administration still has "four more months to go until the end of March," when penalties kick in for those who haven't gotten coverage.

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    Obama, though, recently kicked off his latest effort to promote the benefits of the law in response to mounting criticism about its rollout. States have been promoting their health care exchanges for months, in advance of the Oct. 1 launch. And Obama spent much of the 2012 campaign touting the upsides of the law.

    Whether a new promotional effort will convince young people to come onboard is unclear. Speaking earlier on "Fox News Sunday," Sen. Rand Paul, R-Ky., said: "I don't see any way ObamaCare can work."

    Emanuel was responding to a recent poll that showed that vital age group was shying away from coverage.

    The Harvard "Millennials" poll, released last week, found only 22 percent of young Americans -- defined in the survey as between 18 and 29 years old -- plan to sign up for ObamaCare. "Actuarially, the [Affordable Care Act] depends upon these young Americans signing up," Trey Greyson, director of Harvard's Institute of Politics, said last week. "Our survey shows that the administration has a lot of work to do to get them onboard."

    The Affordable Care Act relies on young, healthy people to sign up. If this doesn't happen, it could create what some have referred to as a "death spiral," where insurance companies are taking on older and sicker Americans, causing premiums to skyrocket and risking the health of the whole system.

    Emanuel, though, disputed the Harvard poll as "not a very useful piece of information," and claimed that in states like California, the percentage of young Americans signing up is consistent with the population itself. He said he doesn't think the "death spiral" is a "real possibility."

    He said he thinks young people will be incentivized to sign up, and noted that the looming penalty will convince more to sign up by March 31.

    Emanuel also tried to rebut complaints that despite the president's promises, people are losing their current doctors. "If you want to pay more for an insurance company that covers your doctor, you can do that," he said.

    As for the problems with the website, Emanuel said the administration is "working diligently" to fix them.

    He continued to compare the rollout to that of major tech products like the iPhone.

    "I know that when I got my iPhone, there were lots of glitches. They send updates for that," he said. "This happens with large-scale enrollment of millions of people."

    Asked whether someone like Health and Human Services Secretary Kathleen Sebelius should be fired over the botched launch, he would not say. "He'll make a decision," Emanuel said of the president, adding that the decision not to appoint a "CEO" to oversee the launch was clearly a "mistake."