Sun Tzu wrote on Dec 26
th, 2015 at 12:38pm:
Do you mean like the intelligence operation that failed to prevent 9/11?
9/11 was a massive intelligence failure. Particularly with regards to the CIA not sharing information with the FBI. The FBI was actually searching for at least one of the hijackers and wasn't even aware that he was in the USA but the CIA were.
Sun Tzu wrote on Dec 26
th, 2015 at 12:38pm:
There is no intelligence in the USA immigration system. They can arbitrarily refuse entry and do so as they please. If they had any real evidence against any person they prohibit they could easily have performed interrogations by allowing them into the USA and then intercepting them there. However they can't do that because when people enter the USA they have rights.
There is a great deal of intelligence in the US immigration system, but it does have flaws. It is not perfect but no system is.
You suggest that if they had evidence against a person that they would be able to let them in, and then intercept the person when that person is in the US.
That is only if the person is currently planning an attack and ready to carry it out, and only if you are aware of their plot.
However, that is often not the case. Instead, through the intelligence process the USA may become aware of things about a person that may put them as a potential threat on the threat matrix and as a result, would rather not have that person visit the US in the first place. That information is not necessarily limited to what the passengers may have said and done in the past, but includes what their associations are including people they may be related to or know in the US.
This isn't James Bond stuff.. It's usually based on having a person assessed for being a threat on a threat matrix.
There is usually a lot more done behind the scenes to come to a decision like this.
Sun Tzu wrote on Dec 26
th, 2015 at 12:38pm:
Before people enter the USA they have no rights against injustice by USA immigration. That is why arbitrary unexplained prohibition is practiced at country of departure.
They have no rights when they arrive either. They're technically not in the US until they pass customs and immigration and if customs and immigration decide the person is a threat then they'll get sent back to where they came from.