How does Pumpkin's death affect Johnny?

Johnny was traumatized by Pumpkin's execution:

Johnny put his hands to his face. It was wet and his hands were shaking. He thought of that blue smock his mother had made him, now torn by bullets. Pumpkin had wanted so little out of life. A farm. Cows. True, Rab had got the musket he craved, but Pumpkin wasn't going to get his farm. Nothing more than a few feet by a few feet at the foot of Boston Common. That much Yankee land he'd hold to Judgment Day. (ch 9)