JUDY WOODRUFF:

For more now on the terrorist attacks in Belgium, U.S. foreign policy and the race for the White House, we turn to the other Democratic presidential candidate, Vermont Senator Bernie Sanders.

Senator Sanders, welcome. And, first of all, congratulations on your wins yesterday in Utah and Idaho.

I know you know, as the voters were going to the polls in those states, though, on the other side of the Atlantic, the city of Brussels was reeling from this terrible set of terrorist attacks.

Secretary Clinton said just a short time ago that ISIS cannot be contained; it has to be defeated.

Do you agree? And, if so, how?

SEN. BERNIE SANDERS (VT-I), Democratic Presidential Candidate: Well, I think it has to be destroyed.

This is a barbaric organization that is a threat not only to the people in the Middle East, to the people in Europe, but obviously to the people in the United States as well. It has to be destroyed.

And here is how we destroy it. We do not destroy it by doing what we did in Iraq and getting into perpetual warfare. I voted against the war in Iraq. In fact, Secretary Clinton, when she was in the Senate, voted for that war.

What we do, as King Abdullah of Jordan has told us, is we work to put together a very effective coalition of Muslim nations who lead the effort on the ground, supported by the United States, the U.K., France, and other major powers in the air and through training.

Now, in the last year, we have had some success. Ramadi has been recaptured. ISIS has lost about 20 percent of the ground that it controlled. But we have a lot more to do. So, I think what we need is strong coalition.

And, by the way, Judy — and very few people talk about this — we have got to bring in some of the Gulf region countries who have kind of sat it out, countries like Qatar, one of the wealthiest countries on earth, who are spending $200 billion in preparation for the World Cups in 2022.

They're spending $200 billion for the World Cup. Well, they may want to spend some money helping us destroy ISIS. Saudi Arabia, the UAE, Kuwait are going to have to play a greater role.