ROBERT SIEGEL, HOST:
Two years ago this Friday, President Obama put his final stamp of approval on the sweeping health care overhaul.
PRESIDENT BARACK OBAMA: The bill I'm signing will set in motion reforms that generations of Americans have fought for and marched for and hungered to see.
SIEGEL: To hear the president describe it, Americans wanted the legislation. It's a different story if you listen to his opponents. Just last night, Mitt Romney characterized the law and Mr. Obama this way.
MITT ROMNEY: A president who doesn't - hesitate to use all the means necessary to force through ObamaCare on the American public.
SIEGEL: So what does the American public think about the health care overhaul two years in? Well, opinions about the law remain divided along partisan lines.
NPR's Julie Rovner explores why.
JULIE ROVNER, BYLINE: When the Affordable Care Act became law, Democrats predicted that the public would grow to like it. Well, that hasn't happened - at least not yet. Today, public opinion is almost unchanged from when the law was passed. Democrats mostly like the measure. Republicans mostly hate it.
Michael Cannon, an opponent of the law who works for the libertarian Cato Institute, says he's not a bit surprised that its popularity hasn't grown.
MICHAEL CANNON: Even if this law was written exactly as its supporters would have liked, you still can't put lipstick on this pig. The law just takes too much from too many people to be popular with the American public.
ROVNER: And there's one big reason why, says Tom Miller, another opponent who's with the conservative American Enterprise Institute. It's the so-called individual mandate - the centerpiece of the law that requires most Americans to have health insurance or pay a fine starting in the year 2014.
TOM MILLER: There was something fundamentally different about trying to jam the Individual Mandate down the throats of the American people. And even people who had insurance, were buying it, it just didn't resonate with their core gut instincts and their larger values in history.
ROVNER: But supporters say the reason the law hasn't won more love is a lot more complicated. One big reason, says Princeton professor and health care expert Paul Starr, is that so much of the law hasn't taken effect yet.
PAUL STARR: It's impossible really to focus people's attention on what is in it. They're only going to become aware of the specifics of the legislation as we get close to the point where there's enrollment in health plans and where people actually see how the health insurance exchanges work and how the subsidies work.
ROVNER: And there's another big reason for the lack of support. A lot of people who might like the law misunderstand what it actually requires. For example, says former Clinton administration health aide Chris Jennings, polls show that most people don't realize they don't have to drop their employer provided health insurance starting in 2014 and buy their own.
CHRIS JENNINGS: Probably 95 percent of the voting public either meet the individual requirement or are exempt from it. Why aren't these messages coming through better than they obviously are?
ROVNER: One reason may be that the Obama administration has been spending more effort trying to put the law into effect, than to dispel some of the myths about it. Nancy Ann Deparle is the White House deputy chief of staff and was one of the key administration architects of the health law.
NANCY ANN DEPARLE: I really don't think that was our primary job. I really don't. I really think our primary job was making sure that the changes that are happening to our insurance system were implemented in a careful, deliberate, transparent fashion.
ROVNER: Deparle blames the misperceptions, particularly about the pivotal individual mandate issue, on the law's many political opponents.
DEPARLE: It hasn't sunk in part, again, because of the sustained campaign that's been run on the other side, that's been very effective. And you'll be hearing more about it. But the fact is for the vast majority of Americans, they'll just check a box that says: Yes, I have insurance.
ROVNER: But the administration's lack of messaging, not to mention the political polarization around the law, has frustrated some of the law's other supporters. John Rother runs the nonpartisan National Coalition on Health Care.
JOHN ROTHER: What messaging? I think the problem with something that's this controversial is it's always much easier to criticize it than it is to defend it. And given that, I think the advocates for the legislation have been missing in action.
ROVNER: Princeton's Paul Starr says there's another reason that opponents of the measure outnumber supporters. The entire structure of the law - preserving a private insurance system with an individual insurance requirement - was originally a Republican idea. Yet, Republicans have turned against it. And they're not the only ones.
STARR: Many of the people who are unfavorable are actually unfavorable from the left and are unhappy about the law because it isn't a single payer national health insurance plan.
ROVNER: Which may be yet another reason why President Obama is spending a lot more time talking to his Democratic supporters about things other than health care on the campaign trail these days. Julie Rovner, NPR News, Washington.