The United States has two personal banking systems. One of these systems is carefully regulated. It benefits from substantial government subsidies, and it offers extensive protections to consumers. The other system serves the poor. “One of the great ironies in American life is that the less money you have, the more you have to pay to use it,” writes Mehrsa Baradaran at the beginning of her new book, “How the Other Half Banks.” Baradaran is unconvinced that the private sector can offer good banking services to low-income Americans. Baradaran looks for another option — ideally, an institution with a national network of locations already in place and a commitment to public service. If only we had an institution like that! And, of course, we do: the United States Postal Service. Read more.