BRENNAN: Well, what I'm saying is that this has been an evolving process. We continue to upgrade and to enhance our screening procedures and to take stock of attempts by Al Qaida to penetrate our defenses. And we make adjustments then as well. And so we continue to do it. We've already done it since the discovery of these packages the other day. We have made adjustments in it, and so what we're trying to do is be as confident as possible we will be able to detect these packages wherever they may be.
AMANPOUR: And what about cargo planes, where I understand in ABC's reporting that perhaps 90 percent of cargo is simply not screened?
BRENNAN: Well, all cargo aircraft and all cargo coming into the United States is looked upon as something that we need to look at very carefully and identify those packages coming from different places that we need to screen. Sometimes there are different types of screening technologies. Some are with technical means. Some are actual physical inspections. So we look at all cargo coming into the United States as potentially pieces of cargo that need to actually have this intrusive inspection.
AMANPOUR: Is the United States safe from these threats?
BRENNAN: I think the United States every day I think is getting safer and safer in terms of ensuring that we're able to take the steps that will respond to the most recent attempts by Al Qaida to try to penetrate our defenses.
AMANPOUR: The British say that these explosives could have brought down a plane.
AMANPOUR: You say and apparently they were intended for synagogues in Chicago.
BRENNAN: They were addressed to locations that have been associated with synagogues in Chicago. The British believe that these IEDs were going to be detonated while they were on board the aircraft, wherever that might have been. But what we have to do is to look very carefully at whether or not they were going to be detonated on the aircraft or they were intended for the destination, and that's where they were going to be detonated.
AMANPOUR: And very quickly. Even though this is a threat and you are saying you're still investigating it, the fact that it was intercepted, the fact that the underwear bomber did not explode in midair, does that show that they are getting more sophisticated or less able and sophisticated?
BRENNAN: I think it shows that they are trying to again make different types of adaptations based on what we have put in place. So the underwear bomber, as well as these packages, are showing sort of new techniques on their part.
They are very innovative and creative. We need to stay one step ahead of them. So I think this is a good example of the success that we've had, again working with our partners, not relying on a single technology or a single screening procedure. We need to have multiple ways that we can identify these types of threats early and stop them before they're able to be carried out.
AMANPOUR: John Brennan, thank you very much indeed for joining us.
BRENNAN: Thank you very much, Christiane.
AMANPOUR: Now on to politics. Our last ABC News/Washington Post poll before the election shows the Democrats have lost the mantle of change. In 2008, voters who wanted new ideas and a new direction overwhelmingly supported President Obama. But in this midterm election, 57 percent of so-called change voters support Republicans; 36 percent support Democrats.