China is vowing to retaliate after President Trump on Tuesday ordered an end to preferential trade treatment for Hong Kong, while signing a bill authorizing new sanctions against Chinese officials who imposed an authoritarian security law on the semi-autonomous territory. It’s the latest in a series of tit-for-tat moves that have brought U.S.-China relations to their lowest point in decades. On Monday, China imposed largely symbolic sanctions on senior U.S. politicians, including Republican Senators Marco Rubio and Ted Cruz, in retaliation for U.S. sanctions over China’s human rights abuses of minority Uyghurs in Xinjiang province.