The threat has changed from simply worrying about foreigners coming here, to worrying about people in the United States, American citizens - raised here, born here, and who for whatever reason, have decided that they are going to become radicalized and take up arms against the nation in which they were born.

It's a sad indication of where Washington has come, where policy differences almost necessarily become questions of integrity. I came to Washington in the late '70s, and people had the ability in the past to have intense policy differences but didn't feel the need to question the other person's character.

Well, I think the American people have to understand that the Mexican government is committed, in a very substantial way, to eradicating the effect of the impact of the cartels on Mexico. We have - what are called vetted units down there. Units that have been vetted by our law enforcement people there, the people with whom we deal - primarily.

One of the things I learned is that you've got to deal with the underlying social problems if you want to have an impact on crime - that it's not a coincidence that you see the greatest amount of violent crime where you see the greatest amount of social dysfunction.