Ali Shamkhani, a senior advisor to Iran’s Supreme Leader Ali Khamenei, told NBC News tonight that Iran is prepared to finalize a nuclear agreement with the United States. Under the proposed terms, Iran would pledge never to develop nuclear weapons, eliminate its stockpile of highly enriched uranium, limit enrichment to levels suitable for civilian energy use, and permit oversight by International Atomic Energy Agency (IAEA) inspectors. In return, the U.S. would lift all economic sanctions on Iran immediately.