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,

While the announcement is almost certainly bluster to bring attention to illegal immigration and fentanyl smuggling, there are several reasons why it is so risky.

If enacted, they would violate the 2020 deal that the United States inked with Canada and Mexico during Donald Trump’s first term.