Lost in the fog of the U.S. war on Iran to prevent the emergence of a Persian nuclear bomb is any memory of America’s original interpretation of the Treaty on the Non-Proliferation of Nuclear Weapons, or NPT: What is not prohibited is permitted.
Although the June memorandum of understanding that charts a pathway to a negotiated final agreement terminating the U.S.-Iran war makes no reference to the NPT, reaching a shared understanding on the end state with respect to Iran’s nuclear energy program will require a shared understanding of the NPT, as both the United States and Iran are parties to this treaty. Absent such an understanding, the U.S.-Iran war will continue, and it is quite possible the NPT will cease to exist — de facto if not de jure — collateral damage of the war.
The Senate Foreign Relations Committee July 1968 hearings on the ratification of the NPT provided an opportunity for senior U.S. government officials involved in negotiations over the NPT to articulate the U.S. interpretation of the treaty. Senate ratification reflected its concurrence with respect to the understanding of the various provisions of the NPT.
Indeed, both Germany (then West Germany) and Japan, the leading nonnuclear weapons states and major American allies, incorporated the U.S. interpretation of the treaty in their respective declarations and reservations that were attached in connection with signing and ratification of the NPT. Officials of both countries had extensive discussions with their U.S. counterparts to ensure there were no misunderstandings. Crucially, Russia (then the Soviet Union) did not object to the U.S. interpretation of the NPT (including the German and Japanese declarations and reservations), signaling Moscow’s acquiescence.
Iran signed and ratified the NPT without attaching any declarations or reservations. Tehran has never indicated any disagreement with Washington’s original understanding of the treaty.
So, what was America’s original interpretation of the NPT?
First, Secretary of State David Dean Rusk invoked the overarching mantra that served as the key to unlocking the U.S. understanding of the various provisions of the treaty: “The treaty deals only with what is prohibited, not with what is permitted.” He emphasized that the NPT was very narrowly tailored to prohibit nonnuclear weapons states from the manufacture, acquisition, or transfer of nuclear weapons. Accordingly, what was not specifically prohibited was permitted.
Second, William C. Foster, the lead negotiator of the NPT and director of the Arms Control and Disarmament Agency, also emphasized that nuclear activities not prohibited under Article II were permitted. In a written submission extending his remarks for the record, Foster clarified that pursuing peaceful full-cycle nuclear enrichment activities under the safeguards provisions of Article III of the treaty would be permitted: “Neither uranium enrichment nor the stockpiling of fissionable material in connection with a peaceful program would violate Article II so long as these activities were safeguarded under Article III.” He added that plutonium-powered reactors and fast breeder reactors under safeguards were likewise permitted.
Third, Deputy Secretary of Defense Paul Nitze inserted into the official Senate records of the NPT hearings a statement to the effect that military uses of nuclear energy not specifically related to nuclear explosive devices are not prohibited and therefore permitted under the NPT. He pointed out, for example, that nonnuclear weapons states could have their own nuclear-powered submarines.
Fourth, Rusk highlighted that the NPT would be inoperative in the event of major war and that in such circumstances the U.S. would be free to transfer nuclear weapons to its nonnuclear allies.
TRUMP’S IRAN AGREEMENT AND THE MIDDLE EAST’S UNTHINKABLE NEXT STEP
President Donald Trump‘s withdrawal in 2018 during his first term from the 2015 U.S.-Iran nuclear deal signaled he had second thoughts regarding the 1968 U.S. understanding of the NPT. Trump’s Feb. 28, 2026, decision during his second term to launch a war against Iran in effect confirmed his rejection of the original U.S. understanding of the NPT.
In the negotiations with Iran, Trump’s ultimate challenge will be to negotiate with himself and finally come to terms with America’s original understanding of the NPT. Failure to do so would mean a continuation of Trump’s quixotic war against Iran to prevent the perceived emergence of an unexpressed desire to birth a yet to be conceived Persian nuclear bomb that would be delivered by a so far nonexistent intercontinental ballistic missile.
Samir Tata is the founder and president of International Political Risk Analytics, an advisory firm based in Reston, Virginia, and author of the book, Reflections on Grand Strategy: The Great Powers in the Twenty-first Century.