A compelling case can be made to develop a NATO’s missile defence system in response to the advancement of missile technology and the danger of nuclear weapons. However, this development also undermines Russia’s retaliatory capacity, and consequently heightens the offensive potential of nuclear weapons. This article explores the offence/defence posture of NATO’s missile defence plans in terms of both capabilities and strategy. It is argued that NATO is incrementally increasing the strength and reach of its missile defence components, while rejecting any international treaty to regulate and limit their future expansion. This corresponds with a strategy of achieving invulnerability through counterforce and utilising NATO as an ‘insurance policy’ against Russia, to be activated when conflicts arise. We conclude that NATO has the capacity to distinguish between an offensive and defensive posture by discriminating between potential targets, but it has displayed no intention to do so.