U.S. President-elect Donald Trump's vow to impose tariffs on China and Mexico unless they stem the flow of fentanyl and migrants across the U.S. border could impel deeper cooperation from those governments on drug policing,

Donald Trump, poised to return to the White House, is pursuing a hardline strategy to stem fentanyl’s flow into the U.S. He plans steep tariffs on China and Mexico, nations central to fentanyl precursor production and trafficking.

President Joe Biden's administration has been quietly working with Chinese officials to help stop the flow of fentanyl into the United States. Now, Donald Trump is putting it at risk over his promise of tariffs on China,