The Green Papers 15% threshold no one receives 50% no one receives 50% no one receives 50% 15% threshold no one receives 50% no one receives 50% 15% threshold District of Columbia, 15% threshold 15% threshold no one receives 50% 15% threshold no one receives 50% 15% threshold no one receives 50% District of Columbia, no one receives 50% 15% threshold no one receives 50% 15% threshold District of Columbia, District of Columbia, no one receives 50% rules for the DC convention District of Columbia, District of Columbia, District of Columbia, 15% threshold District of Columbia, District of Columbia, 15% threshold no one receives 50% 15% threshold no one receives 50% no one receives 50% no one receives 50% District of Columbia, District of Columbia, 15% threshold District of Columbia, District of Columbia, no one receives 50% 15% threshold 15% threshold The Green Papers District of Columbia, District of Columbia, DC rules for the DC convention District of Columbia, 15% threshold District of Columbia, 15% threshold register their presidential preferences District of Columbia no one receives 50%