Literature Review: Tinderbox Hypothesis, Michael D. Wallace, Paul F. Diehl, and Mike Horn

• Wallace, Michael D. 1979. "Arms races and escalation: some new evidence." Journal of Conflict Resolution 23: 3-16.
• Wallace, Michael D. 1982. "Armaments and escalation." International Studies Quarterly 26: 37-56.
• Diehl, Paul F. 1983. "Arms races and escalation: a closer look." Journal of Peace Research 20: 205-212.
• Horn, Mike. 1984. "Arms races and the likelihood of war." Presented at the annual meeting of the International Studies Association, Atlanta, GA, March 27-31.

Wallace (1979, 1982) presented the first attempt to develop a comprehensive list of arms races and test the arms race hypothesis. He constructed his list of arms races by examining the military expenditures of participants in serious disputes, specifically those involving at least a threat to employ force prior to those disputes. Wallace's arms race index attempted to capture not only the growth in military expenditures of an arms race but also the underlying conflict between the racing parties by searching for arms races prior to serious disputes. However, this procedure would miss any arms race that did not end in a serious dispute, and consequently cannot provide a complete test of the arms race hypothesis. Instead, Wallace tested whether arms races made escalation to war more likely, or what could be termed the "tinderbox hypothesis." The tinderbox hypothesis states that arms races do not necessarily cause wars, but they do create an inflammable situation between the racing nations where even the slightest spark can

push a blaze to war.

Wallace found impressive results supporting the tinderbox hypothesis: 23 of the 28 disputes preceded by an arms race escalated to war. However, Wallace's determination of arms races and his accumulation of the results suffer from two methodological flaws: His arms race index may have been misleading, and he decomposed multilateral disputes into separate dyads (see Weede, 1980; Altfeld, 1983; and responses by

Wallace, 1980, 1983).

Diehl (1983) and Horn (1984) reanalyzed the tinderbox hypothesis using the same data as Wallace but different arms race indices, and without decomposing each dispute into separate dyads. Both required both sides' average growth in military expenditures to exceed certain thresholds over a set period of time prior to the dispute. Dichl (1983) found that only 3 of 12 disputes preceded by an arms race escalated to war. Horn (1984) found that at most 60% (9 out of 15) of 6-year arms races and 46% (6 out of 13) of 12-year arms races ended in war. These reanalyses suggest that the tinderbox hypothesis is only partially true; disputes preceded by arms races do escalate to war more often than other disputes, but they do not overwhelmingly escalate to war.

From: Morrow, James D. 1989. "A Twist of Truth:  A Reexamination of the Effects of Arms Races on the Occurrence of War."  Journal of Conflict Resolution 33(3): 500-529.