Sure some people coming across the border are carrying drugs....in "insufficient" quantities...in an attempt to make some money. Cash is king.
But it's not the dark ages...most of it is "transporyed" by truck, boat, plane, tunnel, homemade subs, or drones. Many times facilitated by people that live here and know the terrain and area they're dealing with better than any immigrant.
A wall is about as "effective" of a solution to any of this ....as cutting your leg off and putting a band aid on it is.
You block off "one" opening...but like hacking...there's always another route.
All this wall will serve as IMO...is an expensive monument to someone's fragile ego, let him build a statue instead for his worshipers to kneel at... and let the taxpayers spend the money on something we really need...like better healthcare.
That's my "ogic".