The ongoing criminal trial of Linda Sun, a former aide to two New York governors, on illegal foreign agent charges highlights what prosecutors say is China's large-scale operations to influence the U.S. government and the public at large to back Chinese Communist Party policies. What began as a case of illegal Chinese influence expanded over the past year as prosecutors added corruption charges against Ms. Sun and her husband, Chris Hu. Ms. Sun worked for Gov. Andrew Cuomo and current Gov. Kathy Hochul, both Democrats, and is charged with illegally using her official position to promote China's interests in blocking officials from Taiwan and curbing statements related to China's human rights abuses of Uyghur minorities. Ms. Sun and Mr. Hu have pleaded not guilty to more than 30 federal charges. Those charges include operating as an illegal Chinese agent, visa fraud, wire fraud, money laundering, bribery, conspiracy to defraud the United States and tax evasion.