The 1967 Outer Space Treaty is the foundational framework of international space law that has succeeded in effectively governing outer space. However, it is becoming increasingly possible that a major space power, or a group of States, may consider withdrawing from the Outer Space Treaty, particularly in view of the current trend towards nationalistic political populism and isolationistic foreign policies to selectively withdraw from certain key international institutions and treaties. The Outer Space Treaty could be one such treaty, especially in relation to the exclusive national exploitation of space-based natural resources by private entities, and threats to national security. Such withdrawals would likely have serious implications for global space governance, which is essentially based on this Treaty. This paper critically addresses some of the most serious legal issues related to the void that such withdrawal might create in the prevailing international governance regime for outer space.