Hank van den Berg is afraid the U.S. will go to war with Iran. He doesn’t believe that war is justified, that it would solve any problems. He wrote a letter saying as much, and he sent it to the International Herald Tribune, where it was published earlier this year. Not long afterward, he received a letter from an Iranian man, a banker and an economist in Tehran, who was glad to read a letter from an anti-war American. Van den Berg, associate professor of economics at the University of Nebraska-Lincoln, began trading e-mails with the Iranian banker. They discussed...