The combination of Tim's indecision about the cattle, Sam's boldness in running after the thieves, and the cattle thieves' simple terror of being caught and executed, combine to doom Sam. It seems brutally unfair that Sam, who so longs for glory, reaches a crisis point entirely free of camaraderie, glory, or romance. The authors seem to be gently pointing out the youthful foolishness of assuming that your wartime experience will bring you glory and honor. Sam survived every battle and hardship, but he cannot survive the fussy and underhanded bureaucracy of his own side. He is wrongly convicted as an example to the rest of the men. In these chapters, Tim has his first longed-for chance to show off his tavern-running expertise to Sam by opting against slaughtering the cattle, and he fails catastrophically. He harms not himself or his tavern but his brother. Like any adult, Tim has done his best to make a good decision, but has chosen wrong.
Chapter Thirteen deals primarily with the hierarchies of armies and their lack of concern with the death of an individual. Sam has served his side loyally for three years and yet when he is caught in a suspicious situation, his good track record is forgotten. To even speak with the officers, Tim must beg for permission, wait hours on end, plead his case repeatedly, and simply hope for good luck and good timing. The meetings with Putnam and Parsons show Tim only that military high-ups consider themselves too important and busy to spend time defending or sympathizing with their men.
The trial is predetermined according to the whims of people in charge. It does not operate on a system of fairness or actual inquisition into facts and histories. Putnam needs a scapegoat, and Sam's life is worth nothing to him. Tim and Mrs. Meeker are helpless in the face of General Putnam's decision, and their repeated efforts to free Sam only emphasize how thickly guarded and quick to judge the officers of war have become. The men with whom Tim deals lack emotion, and we sense that Sam never belonged with them in the first place. He is a passionate, loyal, loving man, and he has an idealism these officers lack.
The changes in Mrs. Meeker show how the strain affects her. She loses hope entirely and hardens more than she did after her husband's death. Seeing her son placed in such a dire and unjust situation breaks Mrs. Meeker's heart and leaves her silent and vacant. She finds comfort in drinking. Tim responds by acting practically and pressing on in his mission to free Sam. Tim does not mention feeling responsible for Sam's capture, but he steps fully into the responsibility of helping Sam escape his unlucky and unfair fate. Oddly enough, the person who seems most calm about Sam's sentence is Sam himself. He seems resigned to what will happen and he understands it, given the smart lies told by the cattle thieves and his absence at the Betts' house. He is even able to make jokes, keeping up his demeanor and courage. We admire Sam here more than ever, as he makes the valiant effort to bolster his own and his brother's morale.