http://www.businessweek.com/articles/2014-12-18/more-medicaid-patients-less-money-for-doctors
With about 63 million enrollees, Medicaid serves more patients than Medicare, which has about 54 million beneficiaries. (Some people are eligible for both.) But Medicaid doesn’t have the same political clout. Medicare is a top priority for the influential AARP lobby, and its older beneficiaries are more reliable voters than generally younger and poorer Medicaid recipients.