to pressure the respective governments in Canada and Mexico to do more about drug trafficking and migration.
How about the US doing more to stop drug trafficking and migration. At least during the Biden administration, the US border was wide open as even those that were caught were immediately released. As for drugs, the CIA's involvement has been documented in several books, not to mention movies... Whatever reasons Trump has, it's not about drugs or illegal immigrants.. just my two cents..
Good point, I think the way more effective approach would be to secure one's own border, implement stricter immigration laws and also to enforce them. Without effective policy and enforcement it's really pointless what happens at the border.