“For 20 years, three presidents of both major parties proclaimed that an Iranian nuclear weapon was contrary to American and global interests—and that they were prepared to use force to prevent it,” Kissinger and Shultz wrote. “Yet negotiations that began 12 years ago as an international effort to prevent an Iranian capability to develop a nuclear arsenal are ending with an agreement that concedes this very capability, albeit short of its full capacity in the first 10 years.”

“Mixing shrewd diplomacy with open defiance of UN resolutions, Iran has gradually turned the negotiation on its head,” they wrote. “Iran’s centrifuges have multiplied from about 100 at the beginning of the negotiation to almost 20,000 today. The threat of war now constrains the West more than Iran. While Iran treated the mere fact of its willingness to negotiate as a concession, the West has felt compelled to break every deadlock with a new proposal. In the process, the Iranian program has reached a point officially described as being within two to three months of building a nuclear weapon. Under the proposed agreement, for 10 years Iran will never be further than one year from a nuclear weapon and, after a decade, will be significantly closer.”

Kissinger and Shultz pointed out the difficulties of ensuring Iran would abide by the deal. “In a large country with multiple facilities and ample experience in nuclear concealment, violations will be inherently difficult to detect. … The agreement’s primary enforcement mechanism, the threat of renewed sanctions, emphasizes a broad-based asymmetry, which provides Iran permanent relief from sanctions in exchange for temporary restraints on Iranian conduct.”