Clifford Mumm, a former executive with the Bechtel engineering and construction firm who oversaw infrastructure repairs in Iraq after 9/11, has given to the most presidential candidates: $2,700 to Klobuchar, $2,700 to Biden, $2,800 to O’Rourke, $2,800 to Buttigieg and $4,300 to Marianne Williamson, an author and activist. His wife, Christine, also gave $500 to Williamson and $2,800 to Buttigieg.