Every year, criminals and cheats pilfer more than $100 billion-that's $40 billion more than Bernie Madoff scammed off his investors-in federal benefits to which they are not legally entitled. Medicare, Medicaid, food stamps, refundable tax credits, and many other programs are targets for looting.

Government fraud has been in the news lately because analysts are expecting major abuses of the Obama administration's $787 billion stimulus plan. One Deloitte expert argued that "swindlers, con men, and thieves could siphon off as much as $50 billion" of stimulus funds, which are vulnerable because policymakers are under pressure to shovel it out the door quickly.

Even more troubling is the potential for fraud and abuse created by President Obama's other big spending proposals-particularly his giant health-care plan. Obama wants to inject hundreds of billions more tax dollars into federal health care instead of fundamentally reforming Medicare and Medicaid-broken programs that are already subject to Madoff-sized larceny. That is incredibly unfair to those of us paying the bills.

Take Medicare. The Government Accountability Office reports that the program makes about $17 billion in improper payments each year. And that doesn't include problems in the new $60-billion-per-year prescription-drug plan, which is a juicy target for criminals. Harvard University's Malcolm Sparrow, a specialist in health-care fraud, recently testified to Congress that official estimates are "lacking in rigor," are "comfortingly low and quite misleading," and exclude many kinds of fraud and abuse. He thinks that as much as 20 percent of the federal health-care budget is consumed by fraud, which would be $85 billion a year for Medicare.

The bottom line is that the enormous size and complexity of federal health programs results in a huge waste of taxpayer funds.

Medicare makes a staggering 1.2 billion electronic payments each year, making it highly vulnerable to cheating by health-care providers and organized-crime rings. Criminals need only fill out the government forms carefully and the "claims will be paid in full and on time, without a hiccup, by a computer, and with no human involvement at all," according to Sparrow. A perfect example is the recent case of a high-school dropout in Miami who was able to singlehandedly bilk Medicare out of $105 million from her laptop by submitting 140,000 separate claims for equipment and services.

Medicaid is also a huge abuse target. The GAO puts Medicaid fraud at $33 billion-11 percent of state and federal spending on the program. Again, that is likely a substantial underestimate. A former Medicaid investigator believes that up to 40 percent of New York State's Medicaid budget is siphoned off in fraud and improper payments, but New York probably has a worse problem than elsewhere. Using Sparrow's 20 percent estimate instead, Medicaid rip-offs top $60 billion a year nationwide.

How does all this fraud and abuse occur? In many ways, including billing for services and medical equipment not provided, misrepresenting the services provided, and double billing. That last one is common.

Another trouble spot is Medicaid's nursing-home benefits, which are meant for people with low incomes and few financial assets. Since nursing homes are expensive, the program creates a big incentive for higher-income families to falsify their status and apply for the benefits. Indeed, a whole industry of financial consultants helps ineligible seniors hide their income and assets so that they qualify. The result is that the program loses about $10 billion a year to fraudulent claims.

The bottom line is that the enormous size and complexity of federal health programs results in a huge waste of taxpayer funds. The inspector general of the Department of Health and Human Services recently told Congress: "Although it is not possible to measure precisely the extent of fraud in Medicare and Medicaid, everywhere it looks the Office of Inspector General continues to find fraud against these programs."

Medicare and Medicaid are the biggest fraud targets, but this problem plagues all government subsidy programs. Official loss estimates for other programs include $12 billion for the Earned Income Tax Credit, $5 billion for Supplemental Security Income, and $14 billion for unemployment insurance. All in all, the cost to taxpayers is well over $100 billion a year, which translates into a theft of $1,000 or more from every household in America every year.

We think that there are good policy reasons to dramatically cut Medicare, Medicaid, and other benefit programs. But at the very least, the vast magnitude of graft in these programs should give every policymaker pause before pumping even more taxpayer money into the federal subsidy empire.

Chris Edwards is the director of tax-policy studies, and Tad DeHaven is a budget analyst, at the Cato Institute.