This chapter discusses the internal sources of power of the weak states, stressing two elements: first, their geographic situation and its impact on their strength and international position, and second, their military strength, which is a combination of two or more of the elements of strength. Passive resistance comes after a defeat, not before one. The build-up of strong military forces by a weak state, plus its readiness to employ guerrilla or partisan warfare tactics after being occupied by a power, combined with passive or non-violent resistance wherever possible, seems to be the best preparation for fighting or deterring a great power. Under favorable conditions passive resistance can be an important addition to the arsenal of the weak states, but it is never a substitute for internal military strength or external support. Geography is a prime constraint on the weak states' survival.