When Tom Zuiderveld picked up his phone while driving near his home in southern Idaho last month, he had no idea the call would unravel years of professional relationships and cost his family as much as $125,000 a year. His district manager was on the line with word that three dairy farms he supplied synthetic oil to had decided to stop doing business with him — not because of anything he had done wrong, but because of the politics of his wife. Glenneda Zuiderveld is a Republican state senator aligned with a far-right bloc that has been pushing for some…