As tensions rise in the Persian Gulf, the implications of a nuclear-armed Iran make this scenario worth analyzing and planning for. The issue of a nuclear Iran matters for NATO for several reasons: Iran borders the territory of the Atlantic Alliance and this proximity, combined with its ballistic missile arsenal, would give a nuclear Iran the capability to strike targets in continental Europe. In addition, NATO partners in the Middle East and the Gulf have been expressing growing concerns to NATO over their security in an environment with a nuclear Iran.

Looking at all the dimensions of this strategic conundrum, the latest paper from the NATO Defense College argues that the biggest challenge both for the region and NATO the day after Iran goes nuclear is not the potential for nuclear warfare per se but the risk of increasing subconventional confrontations and of "nuclear hedging" among NATO partners in the region. As a result, a nuclear Iran represents a major test for NATO: it challenges the raison d'être of its partnerships and raises the need for key decisions on the future of NATO nuclear and missile defense systems.