Morris Brown, a primary care physician, says that South Carolina lawmakers’ refusal to expand Medicaid will result in preventable deaths because many people who live near his medical offices in Kingstree and Lake City cannot afford to go to a doctor. (Gavin McIntyre for KFF Health News)KINGSTREE, South Carolina — One morning in late April, a small brick health clinic along the Thurgood Marshall Highway bustled with patients. There was Joshua McC…