Leave it to our leaders in Washington to spend a dollar to save a dime.

Congress just announced that a $77-million computer system put in place last summer to combat Medicare fraud had saved taxpayers $7,591 through the end of the year.

But fraud isn't the program's biggest challenge — America's aging population is. With the boomers approaching retirement and health care costs spiraling upward, Medicare's fiscal path is unsustainable.

Congress must reserve Medicare for truly needy seniors and introduce market competition to pay for their care.

Combating Medicare fraud is the rare policy proposal that both political parties can get behind. By some estimates, fraud in the program costs taxpayers $60 billion a year.

Despite bipartisan interest in battling fraud, congressional efforts to battle fraud simply haven't worked. Worse, the fixation on fraud has distracted lawmakers from taking on the more difficult structural problems that threaten Medicare's solvency.

By 2022, Medicare spending is projected to reach $1 trillion. The program will likely become insolvent by 2024.

Obamacare purports to rein in costs by slashing Medicare payments to providers by about $575 billion.

But instead of using that money to shore up Medicare's finances, Obamacare is set to expand Medicaid enrollment and subsidize insurance for low- and middle-income Americans.

And those planned cuts in Medicare may not ever come to pass. Congress has routinely postponed cuts in reimbursement rates for providers that treat Medicare patients.

Phantom cuts won't save Medicare — and neither will anti-fraud initiatives that don't prevent fraud. Instead, Medicare needs a fundamental overhaul.

The first step? Reserving Medicare for only those who need it.

President Barack Obama is fond of pointing out that Warren Buffett pays a lower tax rate than his secretary. But the president doesn't mention Buffett also receives the same government health benefits as his secretary.

Some 10 percent of Medicare beneficiaries make north of $60,000 a year, and 6 percent pull in more than $80,000 annually. It makes little sense for average taxpayers to pay for the care of seniors with incomes greater than the national median. These comparatively wealthy individuals should pay for more of their care — particularly when Medicare is facing imminent bankruptcy.

But means-testing will only partially solve Medicare's fiscal problems.

Federal officials must also rein in Medicare's costs. But rather than doing so through centrally planned fiat, our leaders should leverage the power of competition to empower patients to spend Medicare dollars efficiently and effectively. And the way to do so is through vouchers.

With vouchers, low-income seniors will have the freedom to shop for the coverage that meets their needs. Both insurers and providers will be forced to compete for seniors' business — and will thus have to work to provide the best possible care at the lowest price.

Some lawmakers are already trying to move Medicare in this market-friendly direction. Rep. Paul Ryan (R-Wis.) and Sen. Ron Wyden (D-Ore.) have put forth a bipartisan plan that offers seniors premium support — a fixed payment with which they can purchase their own insurance. The Medicare reform proposal offered up by Sens. Richard Burr (R-N.C.) and Tom Coburn (R-Okla.) incorporates both premium support and means-testing.

To avert the Medicare crisis, Congress and the White House must address the program's structural problems head on.