The chapter makes two key contributions to the literature on energy and conflict. First, the chapter defines petrostate as a state that produces two million or more barrels of oil per day and obtains revenues from their export equal to or above 5% of GDP, and provides a novel calculation to peg the Soviet Union as becoming a petrostate in the late 1960s or early 1970s, prior to the Yom Kippur oil shock. Second, the chapter directly challenges the energy weapon thesis that petrostates in general and Russia in particular use energy revenues to fund external aggression. I show through case studies of the Leonid Brezhnev and Vladimir Putin tenures that increased energy revenues increase the menu of options available to leaders, but do not mechanistically cause increased use of force abroad, neither do energy revenue shortages mechanistically cause increased interstate aggression.