But in the Obama administration the job is taking on a second, perhaps more daunting, responsibility: shepherding health-care reform legislation through Congress.

Unlike his predecessors, Thomas A. Daschle, President-elect Barack Obama's choice for HHS secretary, will be given an expanded role, leading administration efforts to overhaul the U.S. health system.

"This really creates a new type of secretary," said Charles N. "Chip" Kahn III, president of the Federation of American Hospitals. In the past, "HHS was more or less a service organization to the White House," while White House advisers drove policy initiatives.

In broad terms, Obama campaigned on the idea of reducing medical costs, improving quality and eventually achieving universal insurance coverage. He promised to cover every child and to reduce the average family's medical bill by $2,500 a year. He advocated a greater emphasis on prevention and expanding participation in the government-subsidized Medicare and Medicaid programs.

"There are two aspects to the challenge of pushing for health reform," said Dan Mendelson, a budget and health adviser in the Clinton administration. "One is to get the right concepts together with what Congress wants to do, and the other is managing the disparate concepts and generous egos."

A serious restructuring of the health system will require extensive data and analytic capabilities to dissect the proposed changes and the impact they might have, said Karen Davis, president of the Commonwealth Fund, a private, nonpartisan research foundation. "Right now, there's nothing other than the Office of the Actuary to do back-of-the-envelope estimates," she said.

With the expectation that Daschle, a former Senate majority leader, will focus heavily on crafting and pushing legislation, there will be an even greater need for a strong No. 2. HHS is a collection of 11 agencies including the Food and Drug Administration, the National Institutes of Health, the Centers for Medicare and Medicaid Services, and the Centers for Disease Control and Prevention.

"He'll need to have deputies who are well-versed in the agency as a whole and who can manage the ongoing operation of HHS while he leads the health reform discussions," said Len Nichols, director of health policy at the New America Foundation. One of those will likely be Jeanne Lambrew, a veteran of the Clinton administration and a co-author of Daschle's book "Critical: What We Can Do About the Health-Care Crisis."

Lambrew, in a chapter of a book published by the liberal Center for American Progress outlining a proposed agenda for the incoming president, agreed that fixing the health system is a top priority. However, she noted, "these urgent problems overshadow persistent, neglected and potentially deadly infrastructure gaps in the system."

According to her assessment, the nation's ability to respond to natural or man-made crises is weak, as evidenced by the poor response to Hurricane Katrina. Chronic illnesses such as diabetes have been given short shrift, and little has been done to prepare for the long-term health needs of an aging population.

The Commonwealth Fund, after interviewing two dozen health leaders, issued its own set of recommendations. It urged the next administration to make a "real focus on what it takes to improve health outcomes," as opposed to secondary issues related to insurance markets, Davis said. That means tackling childhood obesity, racial disparities and preventable illnesses.

Both Lambrew and Davis cited several instances in which they said ideology or political philosophy trumped science in the Bush administration. Many of those had to do with sexuality and reproductive health, embryonic stem cells and allowing private firms to shape Medicare insurance plans.

Tommy G. Thompson, who served as HHS secretary during the first term of President Bush, did not dispute criticism that politics factored into promotion of abstinence-only programs and Bush's refusal to fund embryonic stem cell research. But Thompson disputed the notion that ideology extended beyond those issues.

He said the next secretary should act swiftly to stabilize the oft-neglected FDA, appoint "competent administrators" in core divisions such as the NIH and the CDC, and continue to bolster the nation's preparedness for biological, chemical, radiological and nuclear attacks.

HHS spokesman Bill Hall offered a similar list of core challenges, including greater attention to food and drug safety, strengthening terrorism preparedness and moving toward wider adoption of electronic medical records.

In his 2004 State of the Union address, Bush promoted the use of electronic medical records, but the administration's efforts have been slow and modest, several experts said.

Beginning in January, Medicare will provide 2 percent bonuses to doctors who write electronic prescriptions. Mendelson said the administration has the leverage as the largest health-care purchaser in the country to push more physicians to adopt more technology, more rapidly. "They could say, 'If you want the privilege of taking care of Medicare patients, you have to use electronic medical records,' " he said.

In her article, Lambrew suggested using expansions of the Medicaid program -- such as raising income eligibility limits -- to extend coverage to more Americans. It is a strategy the Bush administration often opposed. But even if Obama's HHS is philosophically inclined to permit those expansions, it will not be easy. Most states, which help underwrite the program, are broke.