The relationship between the European Union (EU) and the United States (US) has long focused on issues vital to both parties’ national, economic, military, and energy security. However, US officials have frequently accused the EU of free-riding on American efforts and investments to address these challenges. Today, as both parties face growing security threats due to their critical mineral supply chain vulnerabilities, the question at hand is how the EU will approach this new challenge. By using a Markov decision process, this paper argues that, for the most part, the EU will choose to free-ride off US investments but that US punishment mechanisms are an effective mechanism to prevent such defection.