If a man’s home is his castle, why can’t he tear it down? The new owner of a Frank Lloyd Wright cottage in Glencoe, Ill., has posed that question in the most acute way by applying for a demolition permit. People are usually surprised to learn that America’s historic buildings, no matter how significant, go unprotected unless there is a local preservation ordinance. Even those ordinances are typically toothless, since they can be overruled for reasons of “hardship,” a category so elastic that the inability to maximize the...