There is already robust negotiation in Medicare. Pharmacy benefit managers (PBMs) representing as many as 120 million Americans negotiate rebates that regularly reduce the list price of medicine by as much as 30 percent, but PBMs don’t always pass those savings along to their patients, according to the Centers for Medicare and Medicaid Services. The Congressional Budget Office has said the secretary of Health and Human Services would not be able to negotiate deeper discounts than the private market, unless the government imposed restrictions on the medicine covered. And those restrictions would hurt seniors who depend on the popular Part D drug plans to buy their prescription medicine.