John J Hern Jr is sitting at his desk high above the Detroit financial district when I call him on his cell phone. The setting is striking, located in the tallest office building in Michigan. It is built in the early 1990s in a postmodernist style by noted skyscraper architects John Burgee and Philip Johnson. “There is not a cloud in the sky, it is going to be a short-sleeved type day,” Hern tells me. Hern is friendly and relaxed, and like all good lawyers, he has done his homework, peppering me with questions about The Currency, even before I’ve…