In the event of an occupation of Estonia, Latvia, or Lithuania, a conventional military intervention by allies--including the North Atlantic Treaty Organization (NATO), the European Union, and the United States--would be crucial for the Baltic countries to regain national independence. But Baltic civilians could play a powerful role in their own defense--and, in fact, the Baltic countries' constitutions and national security strategies highlight the importance of the willingness and preparedness of their civilians to meet external aggression with resilience and resistance. Increasingly, Baltic governments consider national military defense to be closely intertwined with nonmilitary capabilities, and each has introduced a whole-of-society approach into high-level strategy and policy documents. RAND researchers sought to better understand the nature and effectiveness of contributions that Baltic civilians could make to a resistance campaign during a notional occupation. In this report, using an original analytical framework, the authors examine historic episodes of Baltic armed resistance from 1940 to 1955 and unarmed resistance from 1955 to 1991. Drawing from this analysis, the authors examine more-recent plans and policies to prepare Baltic populations for crises and consider the contributions that Baltic civilians could make during an occupation scenario by imposing costs on an adversary, securing external support, denying an occupier's political and economic consolidation, reducing an occupier's capacity for repression, and maintaining and expanding popular support for resistance. Finally, the authors present recommendations for how allies and partners can support the Baltic countries in strengthening civilian capacity for resilience and resistance.