My impression is that there has been a lot of both theoretical and empirical research on arms races in the field of international relations, and that this claim is still contested. I therefore find it hard to be confident in this claim.
For example, Siverson and Diehl (p. 214 in Midlarsky, ed., 1989) sardonically note that “[i]f there is any consensus among arms race studies, it is that some arms races lead to war and some do not.” Fifteen years later, Glaser (2004) still opens with:
Are arms races dangerous? This basic international relations question has received extensive attention. A large quantitative empirical literature addresses the consequences of arms races by focusing on whether they correlate with war, but remains divided on the answer.
On one hand, there are several theoretical models that posit mechanisms how arms buildups could causally contribute to wars.
Security dilemma/spiral model: If states can’t distinguish offensive from defensive military capabilities and have incomplete information about each other’s goals—in particular, whether they face a “revisionist” state that would seize an opportunity to attack because it wants to acquire more territory -, their desire for security will compel them to engage in a spiral of arming (e.g. Jervis 1978, 2017[1976]). [While commonly cited as a way how arms races could cause wars, I think this idea is somewhat muddy, and in particular it often remains unclear whether the posited mechanism is an irrational stimulus-response cascade or some reason why rational actors would engage in an arms race culminating in a situation where war is a rational response to an external threat. See e.g. Glaser 2000, 2004. Similarly, it’s unclear whether even in this model the arms race is a cause of war or rather a mere symptom of underlying structural causes such as incomplete information or states’ inability to commit to more cooperative policies; see Fearon 1995 and Diehl & Crescenzi 1998.] A different approach of explaining escalation dynamics culminating in war is Vasquez’s (1993) “steps-to-war” theory.
Costly deterrence: If the opportunity cost of military expenditures required for deterrence becomes too large, and if military spending could be reduced after a successful war, then it can be rational to take one’s chances and attack (e.g. Powell 1993, Fearon 2018).
Preventive war: If a state anticipates that the balance of power would change in an adversary’s favor, they might want to attack now (e.g. Levy 1987). Allison (2017) has popularized this idea as Thucidydes’s trap and applied it to current US-China relations. The worry that an adversary could acquire a new weapons technology arguably is a special case; as you suggest, the 2003 Iraq War is often seen as an instance, which has inspired a wave of recent scholarship (e.g. Bas & Coe 2012).
On the other hand, there has been extensive empirical research on the arms race-conflict relationship. Stoll (2017) and Mitchell & Pickering (2017) provide good surveys. My takeaway is that the conclusions of early research (e.g. Wallace 1979) should be discarded due to methodological flaws [1], but that some more recent research is interesting. For example, several studies suggest a change in the arms race-war relationship post-WW2, contra your suggestion that the relationship has been similar since at least WW1. Of course, a major limitation is that conclusions are mostly about correlations rather than causation. Some examples (emphases mine):
Gibler, Rider, and Hutchison (2005) add to the literature by addressing a potential selection bias present in many studies. They attribute this to the unit of analysis—a dispute—which presupposes that deterrence has already failed. In an attempt to resolve this, they identify arms races independently of dispute occurrence and use this to test if arms races either deter or escalate MIDs. Using a sample of strategic rival dyads between 1816 and 1993, it was shown that arms races increase the probability of both disputes and war. [Mitchell & Pickering 2017]
Gibler, Rider, and Hutchison (2005) study conventional arms races and war. [...] Only 13 of 79 wars identified by the Correlates of War Project from 1816 through 1992 were preceded by an arms race. As well, only 25 of the 174 strategic rivals identified by Thompson (2001) had an arms race before a war. [Stoll 2017]
Important empirical literature has also placed arms racing in a broader theoretical context to improve comprehension. The “steps-to-war” approach introduced by Vasquez (1993) includes arms races as one of a number factors that contribute to an escalation of violence between states. A good deal of empirical work has tested this approach in the decades since it was first introduced (Colaresi & Thompson, 2005; Senese & Vasquez, 2008; Vasquez, 1996, 2000, 2004, 2009; Vasquez & Henehan, 2001).
[...]
Beginning with Sample’s (2000) multivariate analysis, research on the arms race–war relationship has accounted for territorial disputes and other factors that may influence the outbreak of war. The literature had not, however, examined the relationship between arms races and other steps to war. Vasquez (2004) and Senese and Vasquez (2005, 2008) address this and find that other power politics practices (e.g., alliances and rivalry) do not eliminate the arms race–war relationship.
[...]
Building upon these earlier findings, Sample (2012) conducted another analysis that divided the temporal domain into three separate eras: 1816 to 2001, 1816 to 1944, and 1945 to 2001. She further controlled for state rivalries—dividing the data into disputes within rivalry and disputes outside of rivalry—and used three different measures of rivalry to compare the findings. The results showed that mutual military buildups had a substantial impact on conflict escalation to war, between both rivals and non-rivals. This suggests the relationship between arms races and war is not an artifact of rivalry (see Rider et al., 2011, for a contrary view). [Mitchell & Pickering 2017]
Rider, Findley, and Diehl (2011) [...] also study the relationship between rivalries, arms races, and war. The time period of their study is 1816–2000. They use Diehl’s operationalization of an arms race. They find that taking rivalries into account is important to understanding that relationship. In particular, locked-in rivalries (those rivalries that have experienced a large number of disputes) that experience an arms race are more likely to experience a war. [Stoll 2017]
Endnotes:
[1] E.g. Stoll (2017), emphasis mine:
The broader issue is about the basic research design used by Wallace. He did not examine whether arms races lead to war. He looked at dyads that engaged in militarized interstate disputes and asked whether if prior to the dispute the dyad engaged in rapid military growth. If so, Wallace predicted (and his results—with the caveats of other studies noted above—supported this) that the states were very likely to engage in war.
For the moment let us accept Wallace’s findings. Understanding the conditions under which a dyad that engages in a militarized interstate dispute is more likely to end in war is a contribution to understanding why wars happen. But it does not explain the relationship between arms races and war. Even if we accept Wallace’s index as a valid indicator his research design does not allow for the possibility that there may be many arms races that are not associated with disputes. Including these cases may produce very different conclusions about the linkage between arms races and war.
References:
Allison, G. (2017). Destined for war: can America and China escape Thucydides’s trap?. Houghton Mifflin Harcourt.
Bas, M. A., & Coe, A. J. (2012). Arms diffusion and war. Journal of Conflict Resolution, 56(4), 651-674.
Diehl, P. F., & Crescenzi, M. J. (1998). Reconfiguring the arms race-war debate. Journal of Peace Research, 35(1), 111-118.
Fearon, J. D. (1995). Rationalist explanations for war. International organization, 49(3), 379-414.
Fearon, J. D. (2018). Cooperation, conflict, and the costs of Anarchy. International Organization, 72(3), 523-559.
Glaser, C. L. (2000). The causes and consequences of arms races. Annual Review of Political Science, 3(1), 251-276.
Glaser, C. L. (2004). When are arms races dangerous? Rational versus suboptimal arming. International Security, 28(4), 44-84.
Jervis, R. (1978). Cooperation under the security dilemma. World politics, 30(2), 167-214.
Jervis, R. (2017). Perception and Misperception in International Politics: New Edition. Princeton University Press.
Levy, J. S. (1987). Declining power and the preventive motivation for war. World Politics, 40(1), 82-107.
Powell, R. (1993). Guns, butter, and anarchy. American Political Science Review, 87(1), 115-132.
Siverson, R., Diehl, P., & Midlarsky, M. (1989). Handbook of War Studies.
Vasquez, J. A. (1993). The war puzzle (No. 27). Cambridge University Press.
Wallace, M. D. (1979). Arms races and escalation: Some new evidence. Journal of Conflict Resolution, 23(1), 3-16.
My impression is that there has been a lot of both theoretical and empirical research on arms races in the field of international relations, and that this claim is still contested. I therefore find it hard to be confident in this claim.
For example, Siverson and Diehl (p. 214 in Midlarsky, ed., 1989) sardonically note that “[i]f there is any consensus among arms race studies, it is that some arms races lead to war and some do not.” Fifteen years later, Glaser (2004) still opens with:
On one hand, there are several theoretical models that posit mechanisms how arms buildups could causally contribute to wars.
Security dilemma/spiral model: If states can’t distinguish offensive from defensive military capabilities and have incomplete information about each other’s goals—in particular, whether they face a “revisionist” state that would seize an opportunity to attack because it wants to acquire more territory -, their desire for security will compel them to engage in a spiral of arming (e.g. Jervis 1978, 2017[1976]). [While commonly cited as a way how arms races could cause wars, I think this idea is somewhat muddy, and in particular it often remains unclear whether the posited mechanism is an irrational stimulus-response cascade or some reason why rational actors would engage in an arms race culminating in a situation where war is a rational response to an external threat. See e.g. Glaser 2000, 2004. Similarly, it’s unclear whether even in this model the arms race is a cause of war or rather a mere symptom of underlying structural causes such as incomplete information or states’ inability to commit to more cooperative policies; see Fearon 1995 and Diehl & Crescenzi 1998.] A different approach of explaining escalation dynamics culminating in war is Vasquez’s (1993) “steps-to-war” theory.
Costly deterrence: If the opportunity cost of military expenditures required for deterrence becomes too large, and if military spending could be reduced after a successful war, then it can be rational to take one’s chances and attack (e.g. Powell 1993, Fearon 2018).
Preventive war: If a state anticipates that the balance of power would change in an adversary’s favor, they might want to attack now (e.g. Levy 1987). Allison (2017) has popularized this idea as Thucidydes’s trap and applied it to current US-China relations. The worry that an adversary could acquire a new weapons technology arguably is a special case; as you suggest, the 2003 Iraq War is often seen as an instance, which has inspired a wave of recent scholarship (e.g. Bas & Coe 2012).
On the other hand, there has been extensive empirical research on the arms race-conflict relationship. Stoll (2017) and Mitchell & Pickering (2017) provide good surveys. My takeaway is that the conclusions of early research (e.g. Wallace 1979) should be discarded due to methodological flaws [1], but that some more recent research is interesting. For example, several studies suggest a change in the arms race-war relationship post-WW2, contra your suggestion that the relationship has been similar since at least WW1. Of course, a major limitation is that conclusions are mostly about correlations rather than causation. Some examples (emphases mine):
Endnotes:
[1] E.g. Stoll (2017), emphasis mine:
References:
Thanks!