The facts as I understand them:
- Father alerted U.S. consulate in Nigeria that he'd turned extremist
- Press says that his U.S. visa should have been revoked
BUT
- He boarded the flight as an alleged Sudanese refugee without a passport
SO
- If he boarded the plane as an unidentifiable person, what could have been done to prevent it? Taking away his U.S. visa would have had zero effect on whether he boarded the plane...
(I'm not referring to the obvious miss on the part of the security screeners in Amsterdam.)