U.S. Comptroller General David Walker went on “60 Minutes” Sunday to call the new Medicare Part D prescription drug program “probably the most fiscally irresponsible piece of legislation since the 1960s.”

Walker, the head of the U.S. Government Accountability Office, said underfinancing and the aging of the baby boomers make the Medicare drug program a “fiscal cancer.”

With one stroke of the pen, the federal government increased existing Medicare obligations nearly 40% over the next 75 years, Walker said.

“We’d have to have $8 trillion today, invested at Treasury rates, to deliver on that promise,” Walker said.

The funding “is going to come from additional taxes, or it’s going to come from restructuring these promises, or it’s going to come from cutting other spending,” Walker said.