What does that have to do with a free trade agreement?Why do you assume that both Canada and Mexico were abiding by CUSMA?
And yes, now that Canada is looking at the border...there actually is a problem...
More fentanyl has been seized at or near border since the launch of Operation Deterrence than was seized at the entire Canadian border last year. While 43 pounds was seized going from Canada to the United States last year, the OPP, and its municipal and Indigenous police partners have seized 46 pounds.
https://torontosun.com/opinion/columnists/ontario-cops-seizing-fentanyl-at-the-canadian-border
Nice try though.