To give a definitive answer on the construction of this wall I would say starting from the first wall that we humans have built.
The most famous walls of history are the vrino di adrino, the wailing wall, the trojan walls and finally the berlin wall.
Let us reflect a little on the consequences caused by these enormous constructions.
If we think well none of these has helped anything, so we should not ask many questions.
The only thing we can do is put ourselves on both sides of the wall.
If I were an American trump supporter I would feel safe to have a barrier in my city, as it would increase security,but if I were a Mexican I would feel deprived of my freedom because I would not consider it just to allow others to decide my travels dictated by various reasons, above all because I am a ciyttadino of the world and I have the right to go where it is best for me.
My conclusion is to increase multiculturalism to allow everyone to have the same rights and encourage the integration of people from different countries.