Personally, I'd like a wall on our whole 1,900-mile southern border. A 40-foot tall, 12-foot thick beautiful wall! But, with added defensive measures. Motion-sensor machineguns, minefields, electronic surveillance, drones, and actual human guards, patrols. Helicopters, satellites, fixed-wing aircraft, with bombing/machine-gunning capacity. Then back from this monster wall, another row of defensive measures, fences, barbwire, artillery batteries, machinegun bunkers, and tanks! At each legal port of entry, we will stop and search every vehicle, like I mentioned I saw at the Chinese-Hong Kong border. Every immigrant trying to enter the country at the southern border would be searched and detained for at least 24 hours as an extensive background search is conducted. If legal and okay, they'll be allowed to enter. But, we will have agents who will monitor their activity, see where they go and what they do.
Then we will see...
We will see how much this affects the illegal drug trade and illegal immigration. At least we'll be able to further isolate where the problems are. If drugs are still getting in, then where? How? Some of it is getting in now via boats. So! as part of my defensive system, we'll beef-up the US Coast Guard. Give them more assets. Etc..