The spiral model identifies the next step in reasoning about states' behavior after identifying the intensity of the security dilemma. In particular, under given circumstances of the security dilemma, what steps might a threatened state take to derive advantage by attacking first. In other words, the spiral model seeks to explain war. In the spiral model of Jervis, there are two reasons why a state might end up in war. "Preventive war" might take place as one state might decide to attack first when it perceives the balance of power shifting to the other side creating an advantage in attacking sooner rather than later as conditions may not be as favorable in the future as in the present. "Preemptive war" might take place as a state might decide to attack another state first to prevent the other state from attacking or to obstruct the other state's attack because it fears the other state is preparing to attack.