I referenced a 60 Minutes report on Medicare fraud earlier this week. Mark Hemingway adds some additional context:

Medicare fraud amounts to $60 billion dollars a year. That is one heck of a lot of money. In fact, Medicare loses seven times as much money in fraud every year than the combined profits of the 14 health insurance companies on the Fortune 500. Medicare currently covers 46 million people. How much more money will be lost to fraud when an additional 88 million people are dumped off of employer health insurance rolls in favor of a public option?
And remember, one of the primary reasons that the public option is supposedly better than private insurance is low administrative costs. Well, a major reason why private insurance has higher administrative costs is that, unlike the federal government, they make a genuine effort to combat fraud.