The U.S. government has banned American government personnel in China, as well as family members and contractors with security clearances, from any romantic or sexual relationships with Chinese citizens, The Associated Press has learned. Four people with direct knowledge of the matter told the AP about the policy, which was put into effect by departing U.S. Ambassador Nicholas Burns in January shortly before he left China. The people would speak only on condition of anonymity to discuss details of a confidential new directive. Though some U.S. agencies already had strict rules on such relationships, a blanket “non-fraternization” policy, as it...