The Senate last week faced up to the inevitability of making compromises to win 60 votes for a critical overhaul of the nation's $2.5 trillion health-care system. But it also proved that political flexibility doesn't have to mean the goals of reform - expanding health coverage and reducing the growth in costs - get lost in the shuffle.

In fact, the deal that's taking shape to gain moderate Democrats' votes holds out real promise for millions of Americans now without access to affordable health insurance.

While it backs away from a full-blown government-run health plan to compete with private insurers, the proposal announced Tuesday by Majority Leader Harry M. Reid (D., Nev.) would provide an unprecedented expansion of Medicare to people over 55.

That's potentially huge, since it could provide a critical safety net for a working-age population often targeted for layoffs and early retirement when, as now, the economy suffers a downturn.

Despite polls in recent days that seemed to tap into a gnawing cynicism about Congress in general, the nonpartisan Kaiser Family Foundation said earlier surveys suggest the Medicare expansion would be "broadly popular."

The almost knee-jerk opposition to the idea from health insurers and lobbying groups for physicians and hospitals is understandable. It may mean insurers do not get to sign up new subscribers from this age group. And health-care providers have long chafed under Medicare rates.

But the Senate plan also would create a large new market for private insurers by establishing two national health plans run by private insurers with federal oversight to assure consumer protections. Unlike Medicare, the plans would negotiate rates likely more favorable to providers.

So, along with scrapping the so-called "public option" for a government-run health plan, the Senate plan adds up to a win for insurers, hospitals, and doctors.

As for Republican leaders who dismiss what one called the "2,000-page health-care concoction," their quack advice to the nation's 47 million uninsured is to take a seat in the waiting room.

The main concern now is whether the Democrats' consensus plan is affordable - a question soon to be answered by a review from the Congressional Budget Office. While the Medicare expansion won't fly if it's going to bankrupt the retiree health plan, the monthly premiums also must be affordable for the under-64 population needing insurance coverage.

Other moves by the Senate on the cost front offer some hope, particularly proposals to move away from the fee-for-service payments that drive up so much health-care spending. If Reid were to strengthen a proposed advisory board's power to limit Medicare costs, so much the better.

For now, resolving Democrats' differences over the public option moves the nation one step closer to historic health-care reform.