Why is Tehran terrified of US senators meeting with the Iranian opposition?

The Iranian regime has constantly tried to downplay the role and influence of the opposition coalition, the National Council of Resistance of Iran, and its main constituent, the People's Mojahedin Organization of

http://www.washingtonexaminer.com/why-is-tehran-terrified-of-us-senators-meeting-with-the-iranian-opposition/article/2631613