With his recent speech on healthcare, Bill Bradley has moved the worsening plight of the uninsured back into the spotlight. In doing so, he has offered a challenge not only to his main presidential rivals, Al Gore and George W. Bush, but also to a nation too long resigned to accepting the uninsured as an indelible stain on the civic fabric of America.

Just a few years ago, this challenge seemed improbable. After Clinton's complex health plan died in 1994, the best many health reformers hoped for were timid incremental changes that offended few and accomplished little. Since then, however, the growth of medical spending has slowed, making cost containment less pressing. At the same time, roughly a million Americans a year are being added to the ranks of the 44.3 million uninsured, as employers scale back coverage and welfare recipients take low-wage jobs. In George W. Bush's Texas, for example, about a quarter of residents are uninsured-the highest share in the nation.

That this erosion of coverage is occurring at a time of remarkable prosperity makes it all the more troubling. Yet it has also made the problem newly attractive as a target of public action. President Clinton's plan, constructed in the harsh budgetary climate of 1993, was basically a zero-sum proposition in which tough new regulations and mandates would permit expanded benefits and coverage. The proposals considered today are mostly about showering more money and more tax favors on our already heavily subsidized employment-based system.

Bradley's new proposal moves away from this post-Clinton-plan consensus- but only so far. The aims are undeniably lofty: universal coverage for children, near-universal coverage for adults, along with smaller improvements in Medicare. And the proposal carries a hefty price: an estimated $ 65 billion a year, which Bradley says would come from the projected federal budget surplus. The means are varied and sometimes innovative: Parents would be "responsible" for obtaining insurance for kids (Bradley has not specified an enforcement mechanism). Tax credits for health insurance would be made available on a sliding scale, with premiums fully paid for those in lower income brackets. And all Americans would be able to buy into the same plan that provides private health insurance to federal workers, including members of Congress.

Yet the Bradley proposal promises the candy without the bitter medicine. Bradley wants the government to underwrite private insurance for those without it, but he is understandably reluctant to explain how private plans would be kept affordable and secure when premiums rise, employers shed coverage and insurers cherry-pick the healthy. This may be shrewd politics, but it is shaky policy. Under the Bradley proposal, the federal plan would likely attract high-cost patients as employers dump coverage and health plans price the unhealthy out of the market. Without a strict requirement that children be insured, many would likely remain uncovered. And if more or sicker people join the federal plan-or if, as expected, premiums spike upward-the expenditures of the program would likely outrun expected surpluses, whose size remains uncertain in any case.

Still, these complaints should not obscure what is valuable in Bradley's vision. Most compelling is his commitment to universal coverage for children-a goal he correctly likens to the original aim of Medicare, which also targeted a sympathetic population ill served by employment- based insurance. Yet Bradley might have taken the Medicare analogy further. Like others who advocate children's insurance, he wishes to insert a new system of subsidies and government-supported insurance into the existing patchwork of employment-based coverage. This makes little sense. Corporations would continue to drop coverage even faster if subsidized plans existed, and millions of children would inevitably fall through the cracks, as millions do today. (Last year the number of uninsured kids increased by 330,000, to 11.1 million.) A single federal program in which all Americans would be enrolled from birth until 18- Medicare for kids-would be the most effective and courageous way to uphold Medicare's legacy.

But Bradley's proposal at once allies him with a noble cause and separates him from Gore and Bush. Although Gore has also vowed to assist the uninsured, his proposal is more modest, promising neither to achieve universal coverage nor to provide government-sponsored insurance. Gore's main idea is to expand the scattered state programs for children funded by the 1997 budget deal-which to date have managed to cover only a pitiful proportion of uninsured kids. Bush has distinguished himself mainly by trying to limit the expansion of children's coverage. When the Texas legislature considered how to spend the new federal money authorized in 1997, Bush fought to cover only kids in families with incomes below 150 percent of the poverty level, rather than the 200 percent that other states had adopted and that the legislature eventually enacted.

No one should be sanguine about the prospects for meaningful reform, but perhaps we will someday look back on the fragmented initiatives of the late nineties as an early, halting step toward a broader commitment of the kind that Medicare represents. If so, Bradley will deserve a share of the credit. With his proposal, he has helped restart a debate that is necessary and overdue. As Bradley expressed the sentiment in his speech, "It is time to try again-but in a different way."

Jacob S. Hacker, a fellow at the New America Foundation and a junior fellow of the Harvard Society of Fellows, is author of The Road to Nowhere: The Genesis of President Clinton's Plan for Health Security (Princeton).