I believe the Vatican is protected by a very high and formidable wall, as well as having the most restrictive immigration policies of any nation in the world.
The USA has perhaps the most lenient immigration policies of any nation. He also is a fervent anti-capitalist, not noting the irony that these folks are fleeing left wing regimes for economic reasons.
oh by the way, the Lord commanded Nehemiah to rebuild the wall around Jerusalem. Just saying.