Across the country, dozens of private insurers that run Medicare Advantage plans are preparing to pare dental, vision and certain prescription-drug coverage starting next year, according to consultants who have helped them assemble annual bids. Although some planned cuts might not materialize given Congress's history of tabling unpopular measures, the law represents the tip of a broader change. Most Americans know the overhaul is designed to cover the uninsured, a decades-long goal of Democrats. But it also represents a change in how the government spreads its social safety net underneath Americans. Already, it's creating tensions that are a harbinger of debates to come. Since the creation of Social Security and Medicare, younger workers have funded programs for the elderly. It's a compact in which workers paid for retirees with the understanding that they'd be looked after by the generation behind them. The health overhaul diverges by tapping a program for the elderly to help provide insurance to 32 million Americans of younger generations. Nearly half the funding for the law is supposed to come from paying lower fees to hospitals, insurers and other health-care providers that participate in Medicare.