Foreign Policy reports: America’s top negotiator in the Iran nuclear talks offered a surprisingly detailed assessment of Tehran’s existing nuclear capabilities on Monday as she warned that failing to secure a final deal with the longtime adversary would seriously threaten American national security.

The remarks by Wendy Sherman, the undersecretary for political affairs at the State Department, come at a pivotal juncture in U.S. politics as Democrats and Republicans on Capitol Hill wrangle over provisions in a new bill allowing Congress to review a final agreement.

Sherman, speaking at the Religious Action Center of Reform Judaism in Washington, said that failing to reach an agreement would leave Tehran closer than ever to acquiring a bomb.

Without a deal, Sherman said, Iran would expand its nuclear enrichment program to 100,000 centrifuges in the next few years instead of shrinking that figure to 5,000 as agreed in the framework agreement brokered in Lausanne, Switzerland on April 2.

She also said Iran could produce enough weapons grade plutonium to produce two bombs each year. And in terms of uranium enrichment, the country could expand its already significant stockpile of 10 tons of enriched uranium.

In dealing with both of the emerging pathways to a bomb, she said an agreement would result in Iran having “zero weapons grade plutonium” and a stockpile of enriched uranium that is reduced by 98 percent. She added that if the U.S. backs out of a deal widely viewed as fair, international support for sanctions will whither away. [Continue reading…]