so they could put together a nuclear explosive, fairly soon. >> dr. sally he is an expert that studied at m.i.t. i understand you were at the same time but you did know each other and developed a relationship during the course of negotiations. and those negotiations took many years. the united states got involved toward the end and it was very effective, the u.s. involvement. that closed the deal. i'm looking at a question with john kerry, with you, wendy sherman is in that picture. they were intense negotiations at times, but they happened. what is the value of the relationships that were developed, back then, and how could that help in times of remarkable tensions like we are in right now? >> first of all, to give a flavor of the intensity of the negotiations, secretary carrie,