Between 2022 and 2024, 0.1% of all fentanyl seizures were at the northern border with Canada, vs ~99% at the border with Mexico. There’s also an (equally small, relatively speaking) reverse flow of fentanyl into Canada from the US. Not to mention that fentanyl trafficking is completely orthogonal to tariffs, except that the former is used as an excuse to utilize the latter to bully an ally.