Go forward, knowing that you are greater than the challenges of your time.

An aggressor nation or extremist group could gain control of critical switches and derail passenger trains, or trains loaded with lethal chemicals.

I want to reassert again the position of the United States that with regards to Iran, we will not allow Iran to develop a nuclear weapon, period. We will not allow them to develop a nuclear weapon, and we will exert all options in the effort to ensure that that does not happen...The United States stands firmly with Israel, and we have a rock solid commitment to the security of Israel and to the security of its citizens.

I think a quality that a national security adviser must have is the ability to set up procedures.

Frankly, my fundamental beliefs have not changed.

My impression is that Putin feels that he can basically manipulate the West to do what he ultimately wants to achieve, and that he feels he's gotten away with it so far, and that all he has to do is basically play the same game.

Today, I think the attitude is that governing is not necessarily good politics, and the result is that it's much more partisan and much more divided.