Serious disagreements exist between the U.S. and Iran on the nuclear issue. Can substantial progress be made in the third round of indirect negotiations?

Professor of China-Arab Research Institute at Ningxia University, Niu Xinchun: Initially, the US negotiation representative said that the bottom line for the US is as long as Iran does not develop nuclear weapons, everything else is negotiable. But a few days later, the US negotiation representative said that the bottom line for the US is that Iran cannot have any nuclear activities, and all of Iran's nuclear facilities must be destroyed, so this is a significant change. So what is the bottom line for the US now, what compromises can the US make, it is not clear. It is also unclear whether there is a consensus within the US government on this issue. On the Iranian side, it is the same. Iran has not publicly stated what is acceptable and what is not. Some in Iran say that Iran must retain the right to nuclear activities and that Iran's enriched uranium cannot be sent abroad. If so, the gap between the two sides is large, but in the end, both sides will definitely make some compromises. It is not clear what kind of compromise both sides can accept, but the possibility of this round of negotiations making substantive progress and reaching an agreement is very small.