My take on the wall and its function:
The wall is designed to keep the following out:
Drugs
Illegal aliens
Massive convoys of illegal immigrants
Trafficking of women and children
Biological agents, delivered by sick illegal immigrants
Technology that we do not wish to have inside our borders, small nukes or biological technology, jamming systems, etc.
Middle eastern terrorists Hezbollah, Isis, Others
Illegal guns and bombs Ms13 and like gangbangers, a long list
Criminals in general
Spies and agents of other countries.
It is also hoped that the wall will shut down much of the Cartel’s operations rendering them useless.
A partial list, each with many sub-categories.
Additionally, the wall limits immigration and allows us to grant entry to people we need.
And let us not forget that their original plan was to flood the country with illegals who would vote Demo for a generation or two.