As of this writing, it is as yet unclear whether Iran’s maximal concessions will meet the P5+1’s minimum and vice versa, and if the reported details of the proposal at Geneva are accurate, we may have gained an opportunity to review and fix a bad deal. Secretary Kerry is now speaking of months to reach an agreement, but there is certainly far greater hope than at any point to date.

Iran is certainly conducting an unprecedented charm offensive—some might say trying to take the international community on a Persian carpet ride—in the hopes of lifting the sanctions, or of shifting the blame to the U.S. and peeling off countries from the existing sanctions regime, in the event of failure. The question remains whether it truly is willing to forgo a military nuclear capability and reach what would be a painful compromise deal for all. It is certainly worth trying. In the meantime, pending a final agreement, Iran must be made to understand that ongoing sanctions will be fully enforced and that failure to reach a final agreement, or a violation thereof, will lead to their further strengthening.

Chuck Freilich a senior fellow at Harvard’s Kennedy School, was a deputy national-security adviser in Israel. He is the author of Zion’s Dilemmas: How Israel Makes National Security Policy.