Academic says Trump trade war cut off spies China influenced American policies for decades through a covert network of “old friends” — sympathizers and agents — who had penetrated the highest levels of the U.S. government and financial institutions before the Trump administration, according to an academic linked to the Chinese government. Di Dongsheng, a professor and associate dean of the School of International Studies at Renmin University in Beijing, also suggested in a Nov. 28 speech that China’s Communist Party helped Hunter Biden, a son of presumptive President-elect Joseph R. Biden, obtain Chinese business deals. On influencing the United...