Right now the Revolutionary Guards are engaged in a fierce battle with the Iranian government. Mr. Rouhani wants to subject the Revolutionary Guards to political control. One of the things he has been doing systematically is to cancel contracts that the previous administration, Mr. Ahmadinejad's presidency, signed with the Revolutionary Guard-owned companies. That of course makes the Revolutionary Guards fear improvement of relations between the United States and the Rouhani government even more.
As I see it right now, they have no stakes in any kind of negotiated deal, but I think that they are also biding their time. They know that Mr. Khamenei sooner or later is going to depend on them again and will need their support. Let's say in a couple of years from now when the immediate crisis has passed and Iran's economy has stabilized, that foreign companies begin returning to Iran, then Mr. Khamenei could actually go back, when it comes to the nuclear negotiations and say that this and this and this part of the negotiation he does not recognize, and actually support the demands of the Revolutionary Guards. Put simply, his domestic survival also depends on the repressive muscle and arm of the Revolutionary Guards.