Islam is the common denominator in 99% in terrorism worldwide. You will fail if you target individuals, not the doctrine that shapes them. You can't stop a movement by chasing its by-products. You confront the ideas that produce those by-products. You can't neutralize a global movement by treating it like random individual pathology. Again and again, what the U.S. calls “thorough screening” is a joke when it comes to Islamic terrorism. Screening can't detect ideology or intent. The vetting system checks identity, criminal records, and known terrorist ties, not what someone actually believes. Radicalization often happens after entry, long after the vetting window closes. If someone has no criminal record or hasn’t been flagged abroad, they pass. And in many regions, records either don’t exist or are never shared. A jihadist with clean fingerprints and a clean identity profile can walk right through. Add to that the sheer volume, millions of immigrants, refugees, visa-holders, and tourists enter the U.S. each year, and even a tiny failure rate produces real danger.