Although it's not clear what system Janet Napolitano is talking about here when she makes this comment.
Because it's certainly not the system that is designed to keep radical terrorists out of America:
The alleged perpetrator in the recent failed airline bomb attempt had been denied re entry into Britain.
Britain's reason? A pretty good one: He allegedly claimed his intent to study at a bogus University.
His own father, a former economics minister of Nigeria, is reported by the UK's Independent to have warned the U.S. that his son was tied to al-Qi'da almost half a year earlier. In November, his father went to the U.S. embassy in Nigeria to warn the U.S. about his son and these same ties.
ABC's Jake Tapper also notes that on Dec. 16 he bought a round trip ticket with 3k cash and no address or contact info, and on Dec. 24 boarded a flight from Nigeria to the U.S. with no luggage.
These latter two things are not that big of a deal; but in combination with his father', an extremely prominent Nigerian, warning of ties to al-Qida, and Britain banning him from entry prior to that for other reasons?
Seems like, in fact, the system didn't work so well.