Although President Obama has made healthcare his top priority and says the cost of Medicare and Medicaid is "the biggest threat" to the nation's fiscal future. he has not named anyone to lead the agency that runs the two giant programs. The Centers for Medicare and Medicaid Services is the largest buyer of healthcare in the United States. If it had an administrator, that person would be working with Congress on legislation and could be preparing the agency for a new, expanded role, the New York Times notes.