The president will specifically target women and young people, groups that backed him overwhelmingly during his presidential campaigns. During a Mother's Day-themed event at the White House on Friday, Obama will promote the benefits of the law for women, including free cancer screenings and contraceptives, and ask moms to urge their uninsured adult children to sign up for the health insurance "exchanges" that open this fall.
The exchanges are the centerpiece of the landmark overhaul of the nation's health insurance system. Three years after it became law, the measure widely known as "Obamacare" remains controversial, with GOP lawmakers resolving anew to overturn it and many Americans unsure how they'll be affected.
White House advisers acknowledge they struggled in explaining the complex law to the public when it passed in 2010. Now, with the final components being implemented, Obama allies see a fresh opportunity to sell the American people on the merits of measures that will be central to the president's legacy.
"We're in the phase for the actual meat of the law to come online," said Neera Tanden of the Center for American Progress, a liberal group aligned with the White House. "It's important for the public to recognize that the law has tangible benefits to people so they feel comfortable enrolling."
Beginning Oct. 1, consumers can enroll in coverage through health insurance marketplaces called "exchanges" established by the states or the federal government. Coverage under the private plans begins Jan. 1, and nearly 30 million uninsured Americans are eventually expected to take part.
But in order to keep insurance premiums down, young, healthy people will have to join up in order to counteract the costs from seniors and others with health problems.
The uncertainty surrounding the exchanges has many Democrats nervous, including retiring Sen. Max Baucus, D-Mont., one of the architects of the overhaul. He said last month that the health care law is heading for a "train wreck" because of a bumbling implementation.
The president conceded last week that there would be "glitches and bumps" as the final phases of the health care law formally the Affordable Health Care Act are rolled out. But he said most people will be unaffected by the changes that are still to come.
"For the 85 to 90 percent of Americans who already have health insurance, this thing has already happened," Obama said. "Their only impact is that their insurance is stronger, better, more secure than it was before. Full stop. That's it. They don't have to worry about anything else."
Many Republicans strongly disagree, saying the full impact of the law will ripple throughout the economy. House Republicans announced this week that they planned to hold a vote on repealing the overhaul the 37th time the House has voted to repeal all of part of the law. The Democratic-controlled Senate has ignored those votes each time.
House Speaker John Boehner, R-Ohio, acknowledged that the move was largely political, noting that there were 70 new members of the House this year who haven't had an opportunity to register a vote against the health law. As for why Republicans are intent on repealing the law rather than trying to amend its pieces, Boehner said, "I don't believe there is a way to fix this and make it acceptable to the American people."
Administration officials insist it's bad politics for Republicans to keep pressing for repeal. They say the American people don't want to harp on old issues, and cite the law's popularity among young people, blacks, Hispanics and women all demographic groups the GOP has struggled to attract in recent elections.
"It just demonstrates again how out of touch with what the American people want the House Republicans have become," White House spokesman Jay Carney said Thursday.
In reality, a massive number of people are actually uninformed about the provisions of the law. A new poll from the Kaiser Family Foundation showed more than 4 in 10 Americans didn't know the Affordable Health Care Act was still law or was being implemented. About half feel they don't have enough information about the law to know how it will affect them.
Under the law, virtually all Americans must carry health insurance starting next year, although most will just keep the coverage they now have through their jobs, Medicare or Medicaid.