gary samore joins me along with valerie plame who specialized in nuclear weapons.she signed today's letter supporting the agreement. give us your story, your account of when you decided to break with those opposed to this agreement. >> well, after the agreement was announced in mid-july, i took a couple of weeks to study it, =m weigh up the strengths and the weaknesses, and i concluded after looking at it, that the agreement, while not perfect, certainly, was acceptable in terms of preventing iran from building nuclear weapons for at least 15 years. >> the opponents of the agreement, those who don't agree with president obama and including obviously chuck schumer and now menendez who has a couple of motives here, fair to say, they say they can get a better deal. bob corker who is not a bad guy, from tennessee, we can get a better deal. i wonder how that argument works to someone like you. can we get a table somewhere, geneva or new york and get together all the people including china and russia, not exactly the bobbsey twins and cut a better deal? who believes that

and gary samore joins me now.you worked with an organization at least for the past two years, you helped lead an organization that's core mission was to prevent iran from getting nuclear weapons. what made you want to step down? >> well, as you said, i disagreed with the organization on whether or not to support the agreement. in my judgment, this agreement is the best available option to prevent iran from acquiring nuclear weapons. others in the group came to a different conclusion. ii respect that, but under the circumstances, i didn't feel i could continue to be president of the organization at the same time that they were mount ago campaign to -- mounting a campaign to encourage congress to reject a agreement. >> sreenivasan: are they wrong? they seem to be doubling down to convince kong and the u.s. public this is a bad deal. >> i think understand their views. i think there are elements of this agreement i'm not comfortable with. i think it leaves iran with a larger enrichment program than i would prefer and