The annual world illegal drug trade has a volume of 450 Billion USD with about 80 Billion just with Cocaine. Pretty sure this is reason enough to continue history even with a 2000 km fence or wall between Mexico.
There is likely little hope for a real change with a Trump administration of another American style republican thickheads. But hopefully once for future the Americans make it work to elect a politicians able to change things just once for good on this planet hell of neverending tragedies and greedy background players tbinking more in money than real solutions. Not to Forget about, even the prison industry in USA is a Billion Dollar business nobody really wants to stop with.
Actually there are some nations around earth which tried in past decade to find workarounds concerning about to at least not get another flood of addicts into this mess. But none of those workarounds was like the American way with creating another Billion Dollar business out of it as it happened with the now exisisting US pot industry.