Senate Democratic leaders are struggling to preserve the fragile support of interest groups for an overhaul of the nation's healthcare system. The Senate wrestled with amendments that would impose additional cost-control requirements on hospitals, doctors, and drug companies, squeezing out savings beyond the considerable sums those groups had already volunteered to give up, the Washington Post reports. Of particular concern to seniors groups is an effort to strengthen a new independent board that would determine the future of Medicare, raising the possibility of cuts much deeper than those envisioned in the $848 billion healthcare bill.