(FORTUNE Magazine) – For Bill Clinton, eager to have a decent legacy, and for Al Gore, eager to win his own term in the White House, this is the summer to save Medicare and to fight for a prescription-drug entitlement. It looks and sounds like a prescription to win votes from the over-65 crowd, but that's not the half of it. The true target of the initiatives is elderly women.

There are a lot more old women than old men. More than ever, women hold the balance of power in American politics, and right now elderly women are an urgent Democratic priority. "This issue is as much driven by gender as by age," says Sherry Bebitch Jeffe, a Claremont Graduate University political scientist. "This is an angle into the swing group of women--Republicans, independents, moderates--that Gore needs so badly." So badly that the Vice President now puts the issue starkly: "To honor and value our mothers, sisters, wives, and friends, we must preserve and strengthen Medicare."

Move over, soccer moms and waitress moms. The big target in the 2000 campaign is aging moms. Women account for nearly 60% of Medicare recipients, and by age 85, women covered by Medicare outnumber men two to one. Nearly two prescriptions out of three are filled for women. According to the Society for the Advancement of Women's Health Research, women make 75% of the health-care decisions and spend almost two out of every three health-care dollars. But here is the statistic that matters most to the White House. In a CNN trial presidential heat, Governor George W. Bush of Texas defeats Gore by 11 percentage points among women.

The convergence of the senior vote and the women's vote may be the most significant development of campaign 2000. Ordinarily the annual report of the Older Women's League, a sleepy Washington, D.C., lobby group, causes few ripples in the capital; indeed, stacks of last year's volume are still in the office. But this year's edition, called The Face of Medicare Is a Woman You Know, flew out the door, forcing an immediate second printing. Gore himself joined the group for a roundtable discussion.

The Democrats' willingness to court these groups is no surprise. Among women, Clinton outdrew Senator Bob Dole by 54% to 38% in 1996 and handily took the senior vote. The party, moreover, has always had a fondness for big entitlement plans. But the GOP isn't about to surrender those two huge voting blocs. This summer congressional Republicans are working on legislation to grant a new personal income-tax exemption for long-term home medical care. Why the sudden interest? The big budget surplus is fueling talk of a big tax cut, for one thing. But the tax writers are looking as much at the political ledger as at the budget ledger. More than six in ten of those who now receive home health-care services through Medicare are women--and more than two-thirds of nursing-home residents are women. And it's not only the patients who are predominantly female, it's the caregivers at the bedside too; 70% of those who tend chronically ill elders are women. "For something that's so obvious," says Phyllis Greenberger, a Washington, D.C., women's health-care activist, "it's stunning that it took so long to notice."

DAVID SHRIBMAN is Washington bureau chief of the Boston Globe and a Pulitzer Prize-winning political reporter.