u.s. president-elect donald trump nominate ben carson retire neurosurgeon make fail bid republican presidential nomination oversee federal department house urban development refer hud agency budget 48 billion 2016 best know administration public house historically large build poor people able obtain low-cost home large-scale public house country large urban areas still house millions people past decades federal government partnership local governments largely abandon large-scale public house build instead support mixed-income project use vouchers commonly know section help low-income people rent commercial properties large budget allocations hud public house assistance program group include native americans elderly disable people together program budget roughly 40 billion responsibilities agency include carson hud agency oversee public house federal mortgage program