If you build - if you spend billions of taxpayer dollars to build a wall over, let's say, a mountain, if you build a 10-foot wall over a 10,000-foot mountain, and someone is determined to climb the 10,000-foot mountain, they're not going to be deterred by the 10-foot wall. It's a matter of common sense.

In my view, and in the view of a lot of intelligence experts, the terrorist threat that we face now has morphed significantly from the days of 9/11 to homegrown violent extremism. We have to be concerned and focused on homegrown violent extremism, countering violent extremism that exists within our borders.

We are very definitely in a new phase in the global terrorist threat where the so-called lone wolf could strike at any moment.

If you build - if you spend billions of taxpayer dollars to build a wall over, let's say, a mountain, if you build a 10-foot wall over a 10,000-foot mountain, and someone is determined to climb the 10,000-foot mountain, they're not going to be deterred by the 10-foot wall. It's a matter of common sense.

I think that ISIS is a problem and it's really a symptom of a much greater problem.

The Secret Service hates to complain about something. They're secret by nature. They're not boastful; they don't like to be in the limelight. And therefore, they need middle management, i.e., a Cabinet-level person, to be their advocate, to Congress, to the White House, to ensure that they have adequate funding.

Politics, in my judgment, has become not just the means to a policy ends, but it's become the end itself. Politics has become the sport that we all watch, and we all pay attention to.