At the dawn of the Cold War, when President Harry S Truman set forth a plan for national health insurance, the American Medical Association castigated it as 'one of the final, irrevocable steps toward state socialism,' warning that the president's idea 'would not only jeopardize the health of our people but would gravely endanger our freedom.' The nation's largest organization of doctors had, by that point, already been fighting health reforms for a quarter-century, and it would continue to oppose every significant federal attempt to redesign the health-care system straight through to President Bill Clinton's efforts of the 1990s. So, Democrats in Washington were elated -- and surprised -- in July when the AMA urged House leaders to pass a far-reaching health-care bill. But now that the debate has reached a pivotal juncture in Congress -- with the approval of a plan by the Senate Finance Committee on Tuesday -- it is less clear whether the medical association will continue on its new path as a champion for change, or will revert to its role as health reform's most enduring naysayer. 'We don't believe doing nothing is a good solution,' said the group's president, J. James Rohack, as he refrained from endorsing the Senate's approach. 'We are going to work until we can no longer work.' The AMA's wobbly support of the moment is rooted in its recent effort to find common ground among the increasingly splintered interests of the nation's 800,000 physicians, whose loyalty to organized medicine has ebbed for decades. It stems, too, from differences in how the several bills before Congress treat a matter of paramount importance to many doctors: the amount the government pays them to treat older Americans. Last month, in a letter to President Obama and members of Congress, the AMA called for 'critical' changes to the health-care system, including health coverage for all Americans; reducing insurers' power to determine patients' treatment, require cumbersome paperwork and deny coverage to people who already are sick; promoting improvements in medical quality and prevention of disease; and lessening doctors' risk of getting sued for malpractice. But according to health policy specialists on Capitol Hill and beyond, the real linchpin to the AMA's support involves its controversial -- and expensive -- goal to persuade Congress to eliminate reductions in doctors' pay through Medicare that lawmakers tried to set in motion a dozen years ago. Those reimbursement rates carry enormous stakes: Medicare, the federal program for people 65 and older, accounts, on average, for nearly one-third of U.S. doctors' income, and its rates often influence how much private insurers will pay. The reductions in Medicare fees were part of a 1997 law intended to eliminate the budget deficit. Since then, Congress has relented repeatedly. Each year's deferral translates into deeper cuts the following year, so that Medicare is now scheduled to lower doctors' payments by 21 percent in January. In their health-care bills, House committees have devoted $228 billion to keep doctors' payments from falling for a decade. It is the only provision for which House members have not found a way to pay. In the Senate Finance version, however, the reductions would be deferred just one year, as Congress has done before, at a cost of about $10 billion. A senior Senate aide said that Finance Committee Chairman Max Baucus, D-Mont., would like to eliminate the pay cuts in theory but found 'it's hard to get (everything) into the shopping cart.' For the AMA, removing pay changes permanently are 'the price for admission' to a side of the debate it has never joined before, said Jonathan Oberlander, a University of North Carolina political scientist who studies health reform. Until now, 'if you were to characterize the AMA's position on health reform in one word, it would be, `No,' ' Orlander said, noting that its fight against Truman's health insurance plan was at the time the most expensive lobbying campaign in U.S. history. The organization's influence in politics and its own profession began to wane in the 1960s when it opposed the creation of Medicare -- and lost. (Optonal Add End) Its membership has thinned from about nine in 10 doctors early in the 20th century to -- with about 250,000 members today -- fewer than one in three, and some estimates are lower. Organizations representing medical specialties have become ascendant, and doctors are fragmented in other ways: those in rural areas versus cities, those who practice primary care versus more highly paid specialists. 'The AMA is a powerful brand ... but it's been struggling at keeping membership,' said Jack Lewin, head of the American College of Cardiology, who said he favors 'a renaissance of the AMA, but that is going to take years.' Even so, organized medicine retains an influential voice. Campaign finance records show that the AMA ranked third last year among health-care organizations in contributions. And, as President Obama and his aides have wooed segments of the health-care industry, Rohack and other AMA leaders have received repeated invitations to the White House. In the House, the AMA has won concessions beyond pay. They include a provision that would allow doctors to continue taking part in Medicare without participating in a new government-sponsored insurance option. The AMA dislikes the government-sponsored option, although polls suggest that most physicians favor the idea. 