As ad war heats up, White House pushes to enroll millions in Obamacare WASHINGTON (Reuters) - The White House on Tuesday kicked off a six-month campaign to encourage millions of Americans to sign up for health coverage under "Obamacare," an effort in which the president and other political celebrities promote the law's promise of subsidized health coverage. But the massive public education campaign faces a long, difficult slog to persuade nearly 3 million healthy young people with low to moderate incomes to purchase private insurance. Many of them live in conservative, Republican-led states where opponents are spending millions of dollars to discourage enrollment in Obamacare's new, online health insurance marketplaces beginning October 1. In promoting his signature legislative achievement on Tuesday, President Barack Obama sought to leverage his popularity among young adults by joining former President Bill Clinton - who also is popular with that age group - for a "conversation" in New York about healthcare. First lady Michelle Obama and Vice President Joe Biden also are joining the Obamacare campaign, with separate appearances elsewhere. On Wednesday, former Secretary of State Hillary Clinton - who as first lady two decades ago led an unsuccessful attempt to revamp the U.S. healthcare system - will speak about healthcare at the annual meeting of the Clinton Global Initiative, her family's nonprofit foundation. Next week, consumers in most states will begin to see more social media promotions from the Obama administration, targeting young adults in urban areas that are home to many of the nation's estimated 47 million uninsured people, according to senior administration officials. The effort coincides with an expected $1 billion marketing initiative from health insurers, hospitals and health systems, as well as public outreach efforts by groups ranging from AARP, churches and charities to the Walgreen and CVS pharmacy chains, officials said. "This is a Normandy invasion of the health system," said Uwe Reinhardt, a healthcare economist at Princeton University. Eventually, lower-income people will be pleasantly surprised at how little health insurance will cost them with the subsidies. Administration officials are confident that the Patient Protection and Affordable Care Act's initial six-month enrollment period, which runs through March 31, will meet its target of extending coverage to 7 million uninsured people, including 2.7 million adults aged 18-35 who are largely male and black or Latino. An estimated 33 million uninsured Americans could benefit from the program, officials say. The enrollment drive will have to overcome waves of ads from Republican, conservative and business groups that say Obamacare amounts to unwanted socialized medicine that will raise costs for businesses, eliminate thousands of jobs and force some people who already have health insurance to pay more for it. Obamacare's critics already have launched a series of ads, ranging from sarcastic to fear inspiring, that are aimed at discouraging young adults from signing up. Kantar Media's Campaign Media Analysis Group, which monitors political advertising, says that more than $500 million has been spent on Obamacare-related political advertising since the program became law in 2010. Anti-Obamacare ads have outnumbered supportive messages by more than a 4-to-1 ratio, Kantar says. Analysts say the massive spending by Obamacare foes has contributed to Obamacare's shaky showing in recent opinion polls. New Reuters/Ipsos polling data showed Tuesday that 46 percent of Americans disapproved of Obama's handling of the healthcare overhaul, passed by Congress four years ago. Up to now, disapproval rates have not reflected the views of younger adults who could benefit from Obamacare. But over the summer, Obamacare's foes began targeting two major demographic targets for the administration: young people and women. Generation Opportunity, a conservative group that appeals to the young, has two "Creepy Uncle Sam" videos that picture young Obamacare enrollees being confronted in a medical examination room by a sinister-looking Uncle Sam. In one, a smiling Uncle Sam startles a young woman during a gynecological exam. "Don't let government play doctor," the video warns. Opt out of Obamacare. The same group intends to hold anti-Obamacare events on 20 college campuses in the coming months. Americans for Prosperity, another conservative group, has spent millions on television ads in selected states that show mothers and other women worrying about whether their healthcare will suffer with the government "in the middle of things." But opposition ads may have difficulty short-circuiting the Obamacare campaign, which will rely heavily on alternative channels such as the Spanish-language cable channel Univision, African-American radio stations, and the social media Web sites Facebook and Twitter. Many of the administration's marketing targets are similar to those in Obama's 2012 re-election campaign. The Obama campaign proved in 2012 that they could defy everyone's expectations by turning out unexpectedly large numbers of young people and Latinos. They're certainly justified in feeling confident that they can do it again," said Elizabeth Wilner of the Campaign Media Analysis Group. The White House's biggest hurdle could be informing people that benefits exist. Only about half of those who would gain coverage know about the benefits, organizers say, adding that most new enrollees may not sign up until 2014. Others disagree, saying the rollout may do well in the 16 states that have their own healthcare marketplaces, including California, but that things might not go as well in conservative "Red" states such as Texas. "California and Texas will look like different countries where healthcare's concerned," said Robert Blendon, who tracks the politics of healthcare at Harvard University. "This is a local implementation issue," Blendon said. It's not a president, first lady, Joe Biden issue. But they don't know what else to do, so they're going with the army they've got, and that's what they know from elections. Additional reporting by Caren Bohan, Mark Felsenthal, Roberta Rampton and Andy Sullivan; Editing by David Lindsey and Ken Wills