Bernie Sanders Sunday called on President-elect Trump to promise to veto any GOP legislation to cut Medicare, Social Security, or Medicaid, using Trump’s position on retirement programs to try to blunt GOP entitlement reform. In a statement, the Vermont senator and former Democratic presidential candidate seized on the assertion that Trump doesn’t want to “meddle” with Medicare or Social Security, made earlier in the day by incoming White House chief of staff Reince Priebus.