Caution is an important quality in a leader, but it has to be caution followed by decision. Caution followed by ambivalence can be a weakness.

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

It doesn't make a lot of sense for us to borrow money from the Chinese to go give to another country for humanitarian aid. We ought to get the Chinese to take care of the people.

I think my best advice would be to separate Donald Trump, the president of the United States from whatever investigation is being conducted by the FBI. I mean, there is something to be said, frankly, about the need for the appointment of an independent prosecutor because the American people are entitled to have a full review of what happened as a result of what the Russians did during our election.

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 suddenly realized at the CIA that I had to make life-and-death decisions about people.

If we don't do something to simplify the tax system, we're going to end up with a national police force of internal revenue agents.