more controversial letter addressed to iran s leaders authored by tom cotton signed by 47 gop senators and on sunday cotton and as secretary kerry debated criticism surrounding the letter. what we did was send a clear message to a did torial regime. it s wrong, unprecedented and i hope it hasn t made it very difficult here. luke russert is on capitol hill. luke, congress wants to have a more substantial role in the talks. are they going to get that opportunity? reporter: it s a good question. the legislation that is at hand which the white house says is potentially problematic to them getting a deal with iran would allow for the united states congress to in fact ratify any deal the administration would make as it goes right now the administration were to make a deal, they do not need the explicit support of congress. under this legislation, if it were moved, it would essentially give them a review.