Drug traffickers smuggle their contraband into vehicles, cargo or parcels and transport them through an port of entry. What they do not do, is illegally crossing the border with the drug, so how will a wall fight this?
Of the 4,000 suspected terrorists who were arrested and who entered our country from January to July 2017, most were in airports, many at the Canadian border and six in the south. Trumps' solution is to build an expensive wall to stop 0.15% of the terrorist. How will it work against others?
Trumps Wall is not a strategy or a consistent policy, it's a political slogan that he's too vain to admit that it was wrong, and that his followers are too stupid to see through.