Former lawmakers have registered as foreign agents for the U.S. branch of Hikvision, the maker of cameras used to monitor Uyghur Muslims in China’s detention camps. The Chinese tech giant Hikvision, accused of helping the Chinese government’s campaign against the Uyghur minority, has turned to former members of Congress to lobby on its behalf as the United States imposes a series of measures limiting its ability to do business with American companies and investors. Former U.S. representative Anthony “Toby” Moffett (D-Conn.), who served eight years in the House until 1983 and now works at the prominent Washington firm Mercury Public...