And we ask the American people to play an important part of our layered defense. We ask for cooperation, patience and a commitment to vigilance in the face of a determined enemy.

It is fair to say there are individuals in the United States who ascribe to al-Qaeda-type beliefs.

Such a system would be very, very expensive and laborious to have, given the kinds of border we have. Scientists and engineers aren't even sure they have the technology to make it work

Now, a lot of what we are doing right now, quite frankly, is because of what happened on Christmas. Many of the things were kind of in the works. We were already planning, for example, the purchase and deployment of advanced imaging technology. You call them body scanners. We call them AITs (Advanced Imaging Technologies).

You can't imagine a world, quite frankly, without a safe and secure aviation system. And so our job is to really focus on that, and what we need to do to keep it safe and secure.

Well, you know, I think in conversations with members of the Senate and others, they all recognize that the issue of immigration is important. It's important to our nation, it's important to our public safety, it's important to our security, it's important to our economic well-being moving forward. And it's not something that's going to go away.

Let me be very clear: We monitor the risks of violent extremism taking root here in the United States. We don't have the luxury of focusing our efforts on one group; we must protect the country from terrorism whether foreign or homegrown, and regardless of the ideology that motivates its violence.