The charges of Iranian nuclear weapons and nuclear-capable missile research cannot be dismissed. But like Iran’s centrifuge expertise, whatever knowhow has been obtained can never be walked back to some earlier state. International experts have developed a healthy respect for Iran’s capabilities. Ali Akbar Salehi, former IAEA ambassador, foreign minister, and current head of the Atomic Energy Organization of Iran, received his PhD in nuclear engineering from the Massachusetts Institute of Technology. Many other Iranian scientists have the wherewithal, too, despite assassinations of several predecessors.

Iran’s breakout capability will remain – even with a freeze and possible future reduction in the number of spinning centrifuges, reduction in the enrichment of uranium from the current 20 percent to 5 percent, and slowdown or redesign of the Arak reactor. Analysts continue to provide a time horizon based on fuzzy information. If the agreement succeeds, Iran will still retain the capability to build nuclear weapons, no matter how many centrifuges remain spinning. If this nonproliferation experiment goes awry, the time horizon for a breakout will shorten considerably.

Much time will be spent trying to figure out what breakout scenario is acceptable. Whatever is agreed, Iran becomes another Japan or Brazil, and quite possibly that’s the goal for now. Iran has made its point: fait accompli. Inspectors or others may catch Iran in prohibited activity which would lead to another dustup and another round of recrimination. But as Iran continues to refine its nuclear narrative, especially with a pause or rollback in place, only a drastic downturn in political relations with the big powers will provide timely warning of an Iranian nuclear weapons program.