The European security environment has deteriorated since 2014, especially following Russia's invasion of Ukraine in 2022. Sweden's accession to NATO in 2024 and the planned increase in defence spending to 3.5 percent of GDP by 2030 imply an accelerated capability build-up, placing high demands on procurement and sustainment. In parallel, electrification and digitalisation are intensifying global competition for critical inputs. Rare earth elements (REEs) constitute such critical inputs, with significant market concentration in China in both mining and, in particular, processing. The EU's Critical Raw Materials Act (CRMA) and NATO's 2024 list of twelve defence-critical raw materials underscore that raw material supply is increasingly a matter of supply security and national security. This study analyses (1) the effect of a supply disruption in rare earth elements on Sweden's gross domestic product and inflation, and (2) which military materiel systems are most vulnerable to such a disruption. The results show a clear duality: the quantitative analysis indicates no statistically significant macroeconomic effect during the period analysed, while the qualitative analysis highlights micro-strategic vulnerability, particularly within the air domain. The absence of macroeconomic effects may be explained by small import volumes relative to the economy and adjustment mechanisms such as stockpiling and substitution; however, this does not preclude risk under more extreme, selective, or deliberately designed disruptions. A key conclusion is that measures should be based on defence capability rather than macroeconomic stability. Against this background, the study recommends:  Strategic prioritisation of neodymium through an in-depth analysis.  Broadening the raw material analysis to a NATO-based portfolio.  An EU- and NATO-integrated supply strategy for the defence sector.