US president-elect Barack Obama on Thursday tapped former senator Tom Daschle to help revamp the country's outdated health care system, one of the top domestic campaign issues during the general election, according to dpa. Daschle will head both the US Department of Health and Human Services and a new White House Office of Health Reform, giving him tremendous leeway to lead the incoming Obama administration's push for legislative reforms to lower costs and extend access to more than 40 million uninsured. Both Obama and Daschle said the current cost of health care was "unsustainable," harming an already weak US economy and eating up more and more of the revenues of small businesses. "If we want to overcome our economic challenges, we must also finally address our health care challenge," Obama said at a news conference in Chicago, noting that health insurance premiums had doubled over the last eight years. Daschle has long been a strong advocate for health care reform, which is regularly a top concern of voters but has seen few significant changes over the past decade. Daschle wrote a book on health care reform and has called for more government oversight of the industry. "We have the most expensive health care system in the world but not the healthiest nation in the world," Daschle said Thursday, calling it the "largest domestic policy challenge." On the campaign trail, Obama promised to make health insurance affordable to all Americans and get a comprehensive deal passed in his first term. But he has resisted calls to make health insurance a legal requirement, something pushed by many fellow Democrats including Senator Hillary Clinton, herself a long-time health care advocate and rival for the Democratic presidential nomination. Daschle, 61, served as the top Democrat in the Senate from 2001 to 2004 and was an early supporter of Obama's presidential campaign. He served as a senator from 1986 to 2004. The former South Dakota senator has already led an outreach campaign over the last few weeks to enlist ordinary Americans' views on health care policy. Voters were able to submit videos and comments at Obama's transition website change.gov - Daschle has responded to some of them. "My goal is to make sure that we have everybody involved," Obama said. "This is gonna be an open and transparent process."