Walls are necessary.
But what is also necessary is an effective system that preserves humanity's fundamental right to move across political borders.
This does not mean a flood of poor people, but rather a slow trickle that is allowed to assimilate.

This means helping out other nations instead of continuously warring. War wastes men, materiel, and the riches of a nation to enrich a small few.

Weak leaders have precipitated this world in turmoil. Strong individuals have to put the lid on the trashcan of anarchy, chaos, and communism.