"I'm so sorry," Col. Charles Preysler told retired Col. David P. Brostrom, his close friend and former colleague. He was sorry that the elder Brostrom's son was dead. He was sorry that he hadn't been able to do more to prevent it. And, although he didn't say so, he was sorry that he'd made an extra spot for Brostrom's son in his brigade. He hadn't wanted the additional burden that came with sending a good friend's son into battle, he recalled. But he also couldn't bring himself to refuse.