The Nuclear Deal That Could Save NATO

The European Central Bank headquarters, Frankfurt, Germany, March 2026 Jana Rodenbusch / Reuters IVO H. DAALDER is Senior Fellow at Harvard’s Belfer Center for Science and International Affairs. Ambassador to NATO from 2009 to 2013. Daalder Listen unlock this feature or Sign in. Share & Download Print unlock this feature or Sign in. Save Sign in and save to read later Copy This is a subscriber-only feature. or Sign in. Chicago MLA APSA APA Chicago Cite not available at the moment MLA Cite not available at the moment APSA Cite not available at the moment APA Cite not available at the moment This is a subscriber-only feature. or Sign in. The debate exposed a fundamental problem with extending U. S. nuclear deterrence to allies, especially if an ocean separates those allies from Washington. An adversary might be deterred from attacking an American ally a U. S. nuclear retaliation; the consequences of a miscalculation would be catastrophic. But that same small possibility would offer little comfort to the ally, who needs to believe that Washington would actually risk nuclear devastation on its behalf. Denis Healey, the United Kingdom’s defense secretary throughout much of the 1960s, postulated what became known as the Healey theorem: “It takes only a five percent credibility of American retaliation to deter an attack, but it takes a 95 percent credibility to reassure the allies.” The Sputnik launch posed a profound dilemma for NATO. The debate was ultimately resolved through a bargain. Washington’s European allies agreed to forgo their right to acquire nuclear weapons in return for a greater say in U. S. nuclear weapons policy and strategy. Although the idea of a costly multilateral force was abandoned, the creation of the NATO Nuclear Planning Group (NPG) provided a vehicle for Europeans to give input into U. S. nuclear planning and for Washington to demonstrate that European security interests were integral to its nuclear strategy and force posture. Reassured, European countries (aside from France and the United Kingdom) agreed to codify their nonnuclear status in the 1968 Nuclear Nonproliferation Treaty. Many European countries retained ground- and air-based systems that could deliver U. S. nuclear weapons deployed on their territory. Today, about half a dozen European countries still deploy dual-capable aircraft that can carry U. These nuclear consulting and sharing arrangements proved far more crucial to reassuring allies than the hard-power measures (such as counterforce targeting, low-yield weapons, and greater precision) that U.