The president-elect’s pledge to use tariffs to stem the flow of opioids from China could backfire if Beijing responds by ending counternarcotics cooperation.

President Joe Biden‘s fentanyl diplomacy with China is under scrutiny as President-elect Donald Trump’s team seeks a harder line to stop the flow of Chinese-made chemicals powering America’s epidemic.

Trump’s past disputes with Beijing have centered mostly on China’s huge trade surplus, not synthetic opioids. Trump expressed admiration, even love, for Chinese President Xi Jinping throughout much of his first term, even as U.S. overdose fatalities soared.