Peter Berck and Jonathan Lipow focus on the evolution of the conflict in Iraq, the improvement in security conditions, and the role of monetary forces. All wars cost money, and unconventional wars are no exception to the rule. Insurgents need funds for a variety of reasons. Weapons need to be procured, and combatants need to be fed and housed. Insurgencies also require popular cooperation. Evidence offered in Berman, Shapiro, and Felter suggests that to a great extent, this cooperation has to be bought. There are a number of ways for insurgents to instill loyalty amongst those with sensitive information regarding their operations. Another tactic could be to offer social services that would assure that the insurgents' continued survival is indispensable to the local population. Two developments probably contributed more to the revaluation than any others. The first was the recent rally in crude oil prices.