Welcome to Off Message. I'm Isaac DeVair.

An American citizen eases the truck out into traffic. She drives it to a location on Pennsylvania Avenue,

midway between the White House and the Capitol building. At 11.09 a.m., she stops in the middle of traffic,

climbs down onto the street, and triggers the detonator.

The bomb explodes with a power of 15 kilotons.

There are more than 80,000 instant deaths, including the president, the vice president,

the Speaker of the House, and the 320 members of Congress pressed when the bomb goes off.

Today's guest, Bill Perry, who is Defense Secretary for Bill Clinton, now is at Stanford.

But he's 90 years old and on a mission to get everyone much more alarmed about the prospect of nuclear terrorism and nuclear war.

Even before all the North Korea back and forth over the last few months,

he didn't think anyone was anywhere near enough focused on this issue

or treating it like the real possibility that he thinks it is.

I will tell you, this interview gave me nightmares.

I realize saying that maybe isn't the best way to keep you listening, but I'm telling you, you're going to want to hear all of this. From what

he thinks would happen in the aftermath of a nuclear terrorist attack, to negotiating with

the North Koreans when he was Defense Secretary and afterwards, to what he'd like to see happen

with current Defense Secretary Jim Mattis, if we do get to the point of the president

actually considering a nuclear strike. Listen to this whole thing and then think about the fact that

he could just be relaxing with his family and his grandchildren and enjoying a nice retirement.

He's 90, but this is a commitment that has him traveling around the country, pushing on it

nonstop. In the context of the trip President Trump

just took through Asia, it's even more interesting, I'd say. We recorded this at a hotel a few

...