Secretary of State Henry A. Kissinger.

For 10 years, U.N. resolutions and International Atomic Energy Agency directives called for a full halt to all of Iran’s uranium enrichment and plutonium production, and unconditional compliance with nuclear inspections, but now, what “was previously condemned as illegal and illegitimate has effectively been recognized as a baseline,” former U.S. Secretaries of State Henry Kissinger and George Shultz wrote in an Op-Ed in the Wall Street Journal on Wednesday.

Standing by itself, the interim agreement leaves Iran, hopefully only temporarily, in the position of a nuclear threshold power—a country that can achieve a military nuclear capability within months of its choosing to do so. A final agreement leaving this threshold capacity unimpaired would institutionalize the Iranian nuclear threat, with profound consequences for global nonproliferation policy and the stability of the Middle East.

Iran’s technical ability to construct a nuclear weapon must be meaningfully curtailed in the next stipulated negotiation through a strategically significant reduction in the number of centrifuges, restrictions on its installation of advanced centrifuges, and a foreclosure of its route toward a plutonium-production capability. Activity must be limited to a plausible civilian program subject to comprehensive monitoring as required by the Non-Proliferation Treaty.

Any final deal must ensure the world’s ability to detect a move toward a nuclear breakout, lengthen the world’s time to react, and underscore its determination to do so. The preservation of the global nuclear nonproliferation regime and the avoidance of a Middle East nuclear-arms race hang in the balance.