“As a weapon, it had a certain symbolic resonance: The notion that radioactive fragments of Superman’s birth world had become toxic to him spoke of the old country, the old ways, the threat of the failure to assimilate. Superman was a naturalized American. The last thing he needed were these lethal reminders of where he’d come from; that he, the son of lordly scientists, had been reduced to toiling in a farmer’s field or minding the general store.”