New York’s attorney general says her three-year investigation of former President Donald Trump uncovered potential crimes in the way he ran his real estate empire, including allegations of bank and insurance fraud. So why isn’t Trump being prosecuted? Attorney General Letitia James didn’t seek to slap handcuffs on the Republican this week, as some of his critics hoped. Instead, she announced a civil lawsuit seeking $250 million and his permanent banishment from doing business in the state. Like many things involving the law and Trump, the reasons James, a Democrat, opted for a lawsuit rather than a prosecution are complicated....