Conflict scholars have devoted considerable attention to the natural resource curse, and specifically to connections between natural resources, state weakness, and civil war. Many have posited a state weakness mechanism-- that significant oil production causes state weakness, and state weakness consequently increases the likelihood of civil war onset. Using standard measures, this paper demonstrates that the state weakness mechanism does not exist in the short or medium term. The methods developed in this paper show that in only two cases is there the possibility of a medium term effect, and the state weakness mechanism is unlikely to be operative even in these two cases. Furthermore, these methods do not rely on assumptions about unmeasured confounders, so this result is robust to the consideration of other risk factors for civil war onset. The state weakness mechanism may still exist in the form of long term effects or an effect that reinforces pre-existing war and/or state weakness. However, the null hypothesis of no long-term and/or reinforcing effect cannot be rejected without the use of additional assumptions.