In the management of loads and capabilities, and/or in the protection of its national interests, the state may find it necessary (or it may have the capacity) to extend its behavior outside territorial boundaries. To the extent that states extend their behavior outside territorial boundaries, they are likely to encounter other states similarly engaged. The theory of lateral pressure signals the intersection of spheres of influence as a significant point at which interactions are likely to evolve into competition, which in turn shapes hostilities that set in place that can rapidly evolve into spiraling conflicts, leading to military competition, and eventually to violence and warfare – usually triggered by an overt act that is perceived as a provocation.
Clearly not all expansion leads to intersections of interests, not do all intersections of interests harness a conflict spiral. This stylistic sketch is remarkably consistent with the historical record of the industrial west and the narratives developed over time to explain the outbreak of World War I and World War II. The quantitative investigations of lateral pressure theory, highlighted later in this chapter, signal the challenges as well as the opportunities and contentions inherent in, and surrounding, quantitative empirical analyses.