International and domestic sources of Russia's military behaviour

The very foundations of the bipolar world order collapsed in 1991 following the fall of the Soviet Union. The Cold War ended, and the newly born state of the Russian Federation faced the challenge of shaping its foreign policy afresh, taking into consideration the newly unipolar environment. As a consequence, in the last two decades, Russia has adopted various (including aggressive) foreign policy tools to implement its political agenda both globally and within the post-Soviet space.Footnote ⁵

Since its economic recovery in 2004, Russia has resorted to hybrid strategies and sometimes even to open conflicts with other nations, mostly with former Soviet republics. In addition to meddling in Ukraine and adding the territory of Crimea in 2014, Moscow has previously opted for a military response against Georgia in 2008. Despite its internal weakness in the 1990s, Russia intervened in several ethnic conflicts in de facto states such as Transnistria, Nagorno-Karabakh, Abkhazia, and South Ossetia (Zürcher, Reference Zürcher2007; Ofitserov-Belskiy and Sushenstov, Reference Ofitserov-Belskiy, Sushenstov and Tsygankov2018).

In the global arena, Russia has openly intervened in the Syrian conflict since 2015 on the side of Bashar-al-Assad, supporting his regime financially and militarily. Russia's intervention has marked a sharp break from its hesitant role in the Greater Middle East after the collapse of the Soviet Union and prompted a review of its goals in the region (Casula, Reference Casula2015). Following the NATO enlargement eastwards in 2004, Moscow has repeatedly expressed its concerns over the potential deployment of missile defence systems in European states near Russian borders and has warned the West about retaliatory actions if Russia's sphere of interests was not seriously taken into account (Roberts, Reference Roberts and Tsygankov2018).

On the Pacific-Asian front, Russia has reinforced its Pacific fleets and strengthened its military forces close to the Chinese border, even though China has often been praised by Kremlin as one of its main economic partners in energy and weapon sales. In the same area, Russo-Japanese relations have suffered from several episodes of territorial violations regarding maritime trade routes (Kuhrt, Reference Kuhrt and Tsygankov2018).

Russia's foreign policy and its involvement in military disputes are usually debated by means of various approaches and theories at the international, state, and individual levels of analysis (Morin and Paquin, Reference Morin and Paquin2018: 58).

Starting at the systemic level, the debate on explaining Russia's international behaviour is mostly framed by offensive and defensive realism. The former suggests that Russia pursues an expansionist policy as its ultimate goal by profiting from its superior relative power (Sherr, Reference Sherr2013). The latter sees Moscow's behaviour in terms of security needs: Russia's assertion is aimed at counterbalancing external threats (Mearsheimer, Reference Mearsheimer2014; Tsygankov, Reference Tsygankov2015). Although the two arguments are presented as theoretically separate, there appears to be room for both offensive and defensive realism in the case of Russia (Götz, Reference Götz2016a: 12–14). On the one hand, Russia has attempted to maximize its power and prestige with all available means, taking advantage of its economic rise (Donaldson et al., Reference Donaldson, Nogee, Nadkarni and :2014). Some European countries have experienced Russia's use of energy stocks as a power leverage for interfering with their internal political issues (Oldberg, Reference Oldberg and Kanet2007; Jonsson and Seely, Reference Jonsson and Seely2015; Siddi, Reference Siddi2018). On the other hand, Russia has been more likely to escalate militarily when its national interests were perceived to be under threat because of external pressure exerted by great powers, especially the EU and the USA (Asmus, Reference Asmus2009; Götz, Reference Götz2016b). Within this framework, the Western states action in the post-Soviet space and the Middle East has been blamed as the cause triggering Russia's assertive response in Ukraine as well as in Syria (Mearsheimer, Reference Mearsheimer2014).

By focusing only on external factors, structural realist approaches fail to address the variances in Russia's foreign policy. We would expect Russia to seek cooperation with Europe if defensive security and economic gain were the driving forces behind its international posture. On the contrary, we would expect conflict if Russia's final purpose were hegemony and territorial expansion (Forsberg and Haukkala, Reference Forsberg, Haukkala and Tsygankov2018). This is not always the case.

According to the state-level of analysis, Russia's involvement in military disputes is a function of domestic regime consolidation (Malcolm et al., Reference Malcolm, Pravda, Allison and Light1996; Light and Cadier, Reference Light and Cadier2015: Ch. 2; Lo, Reference Lo2015). Two alternative explanations follow from this assumption. First, Russia actively resists regional democratic promotion, which poses the danger that it could spill over to Russia itself and consequently threaten the survival of Russia's regime (Ambrosio, Reference Ambrosio2009; Tolstrup, Reference Tolstrup2015). Russia has often condemned Western promotion of regime changes both at the global level and in the post-Soviet space, not only for reasons of balance of power but also because of domestic concerns (Light and Cadier, Reference Light and Cadier2015: Ch. 2).Footnote ⁶ Second, according to the theory of diversionary war, Russia uses the old tactic of diverting public attention from domestic failures by acting assertively towards other powers (Clunan, Reference Clunan2018). Accordingly, the recent phase of diplomatic clashes between Russia and the Western powers is related to Putin's fear of losing political consensus at home (Shevtsova, Reference Shevtsova2015).

The imperative of regime survival offers a valid argument for explaining Russia's military behaviour; however, both explanations suffer from certain limitations. First, Russia's period of conflict with the West started when economic recovery had bolstered the leadership's popularity in 2004, rather than when Putin had any problems with internal support from the end of his second mandate (Smyth, Reference Smyth2014). Regarding popular support, it must be clarified that there is no real sign that public discontent poses a threat to regime stability in the medium term in Russia because of a lack of real opposition (Shapovalova and Zarembo, Reference Shapovalova and Zarembo2011; Odinius and Kuntz, Reference Odinius and Kuntz2015). Second, the fear of democratic spill over does not explain why Russia has also opposed authoritarian regimes – for example, Kurmanbeck Bakiyev during the Tulip revolution in Kirghizstan and Aleksander Lukashenka in Belarus in 2008 – nor why Russia has close relations with Western democratic states.

Drawing on constructivism, a third group of explanations focuses on the role of ideas and culture. Accordingly, Russia's behaviour is not driven by strategic calculus but rather by identity concerns since national interests do not exist per se but may vary according to certain identity discourses (Neumann, Reference Neumann1995; Hopf, Reference Hopf2002; Tsygankov, Reference Tsygankov2013; White and Feklyunina, Reference White and Feklyunina2014). Scholars usually distinguish three competing identity discourses in post-Soviet Russia that influence its external relations: liberal, statist, and nationalist (Kuchins and Zevelev, Reference Kuchins, Zevelev, Nau and Ollapally2012).Footnote ⁷ All of them view the West as its most significant Other ‘in relation to which the idea of Russia is defined’ (Neumann, Reference Neumann1995: 1).

Closely linked to identity and power, status recognition is another important driver of Russia's international behaviour (Smith, Reference Smith2014; Urnov, Reference Urnov2014). Russia's external actions – especially its show of force in international conflicts – would reflect the kind of recognition that Russia aims to have from other great powers (Larson and Shevchenko, Reference Larson and Shevchenko2010, Reference Larson and Shevchenko2014; Forsberg, Reference Forsberg2014).

Finally, some scholars focus on the figure of the leader as a driving force in Russia's decision-making (Galeotti and Bowen, Reference Galeotti and Bowen2014; Charap and Welt, Reference Charap and Welt2015; Gabuev, Reference Gabuev, Rozman and Radchenko2018). Due to a strong concentration of power as well as the popularity of a strong leader, the figure of the Russian president is important for addressing Moscow's foreign policy (Roberts, Reference Roberts and Tsygankov2018: 237). The logical conclusion is that the state foreign policy might have been different if another individual had been in power (Jervis, Reference Jervis2013).Footnote ⁸

This review reveals the necessity of considering many variables at different levels (international, domestic, and individual) for explaining Russia's international behaviour. In our research, we carried out a theoretically informed combination of different factors.Footnote ⁹ Due to data limitations, we focused on the 1992–2010 timeframe, and we took into account only international (relative power, alliance relations, and salience of the bones of contention) and domestic (level of autocracy/democracy and regime stability) variables. Cultural and individual variables were not considered in this preliminary investigation. We are conscious that this implies a substantial simplification, but at the same time, omitting certain factors produces an empirical analysis that is easier to manage.

Research design

Our study examines to what extent Moscow's military behaviour is a function of its relative power (RP), the presence or not of an external ally of the disputant state (All), the territorial salience of the disputed issue (whether it belongs to the post-Soviet space – PSS), the level of democracy/autocracy (Pol), and regime vulnerability (RV). The assumed directions of the relations are as follows:

1. – The growth of Russia's power (RP) increases the probability of its involvement in MIDs.

This proposition, however, deserves some specification. The literature on conflict behaviour has produced contradictory findings: the balance of power theorists (see, e.g. Waltz, Reference Waltz1979) consider a balanced distribution of power as a factor that decreases the likelihood of conflictual behaviour since an equal distribution prompts mutual restraint; conversely, theorists of the preponderance of power (Kugler and Lemke, Reference Kugler and Lemke1996; Rasler and Thompson, Reference Rasler, Thompson, McLaughlin Mitchell, Diehl and Morrow2012), and supporters of the bargaining model of war (Blainey, Reference Blainey and :1988; Fearon, Reference Fearon1995) believe that a roughly equal distribution of power produces miscalculation, increasing the likelihood of conflicts.Footnote ¹⁰ Empirical research seems to be more consistent with the latter position, even if balance of power reduces the probability of escalation once a conflict has started (Reed, Reference Reed2000). Thus, our first proposition is split into two opposing theoretical expectations:

1. – The first affirms that the greater the power gap, the more assertive is the behaviour and the likelihood of Russia's MID involvement (balance of power theory);

2. – The second states that in a situation of balance, miscalculation increases the likelihood of Russia's MID involvement (preponderance of power theory).

The second proposition refers to the role of alliance in affecting the likelihood of interstate war. Despite the fact that literature on alliances is quite vast, scholars have been unable to reach a consensus whether alliances deter interstate conflicts (Fordham and Poast, Reference Fordham and Poast2016; Gartzke and Poast, Reference Gartzke, Poast and Thompson2018; Poast, Reference Poast2019). Although some scholars argue that alliances formed to help in time of need deter the onset of militarized conflicts between contracting states, others posit that alliances are likely to cause conflict due to the logic of the security dilemma (Kenwick et al., Reference Kenwick, Vasquez and Powers2015). Conversely, others have demonstrated that alliance ties reduce the likelihood of the onset of militarized conflict (Kim et al., Reference Kim, Jungmoo and Jae2019). By focusing on defensive alliance, scholars have demonstrated that the formation of such defensive pacts serve as a costly signal that provides ex ante information to potential challengers that the state target is likely to receive assistance from its allies in the event of military conflict (Leeds, Reference Leeds2003). Many analysts have indeed made the Article 5 from the NATO membership the key factor of deterrence against Russia's aggression, especially in the post-Soviet space (Johnson, Reference Johnson2015). Thus, our second proposition is:

1. – The lack of an external ally (All) supporting a target state will incentivize Russia's MID involvement.

The third proposition is derived by the territory-centred (or issue-centred) approach to studying causes of war and dynamics of conflict. Within this approach, some scholars have contributed to the findings on contiguity and war onset by explaining that wars are not only concentrated among neighbours because contiguity provides an opportunity to war, but also (and above all) because territoriality, under the right circumstance, provides a motivation for war. Others scholars have considered the character of the dispute, namely the issue states fight over, as determinative of state action over territorial disputes. In particular, issues that are seen by decision makers as more ‘salient’, or important, are expected to be more likely to lead to militarized conflicts and harder to resolve to both sides' satisfaction. In the case of Moscow's military behaviour, it has been widely written about the significance – whether material or iconic – that the post-Soviet space represents to Russia's national interest.Footnote ¹¹ The third proposition is:

1. – A high territorial salience of the dispute (in or out of the PSS) will incentivize Russia's MID involvement.

The fourth proposition looks at domestic political dimensions – in particular, the regime type – as the main driver of a state foreign policy:

1. – A low level of democracy (Pol) will incentivize Russia's MID involvement.

This proposition derives from the democratic peace theory, whose main argument is that democracies are less war prone than other regimes (at least vis-à-vis other democracies).Footnote ¹² Conversely, less democratic regimes are more inclined to get involved in military conflicts. Although the causal logic that underpins democratic peace theory has been critically discussed,Footnote ¹³ the argument has been used to address Russia's foreign policy. In particular, some scholars not only point at the authoritarian nature of the Russian regime as the main source of Moscow's assertive foreign policy but also holds that Russia's relations with the post-Soviet space is affected by Russia's fear of democratic contagion.Footnote ¹⁴

Finally, the fifth proposition derives from the diversionary theory of war according to which, leaders use force abroad in order to divert public's attention from domestic failure or to increase their domestic political support:

1. – A high/low level of the regime vulnerability (RV) will incentivize Russia's assertive military behaviour. In this case, we have to formulate two opposing propositions due to the lack of a strong consensus in the literature on the link between Russia's international behaviour and domestic turmoil.

By fomenting the idea of an external enemy by means of extensive state-led media campaigns, the Kremlin manages to motivate and unify its population through what is usually known as the ‘rally around the flag’ effect (Filippov, Reference Filippov2009).

Data analysis

The results of our research are presented in Tables 1 and 2. Table 1 presents the results of the bivariate analysis, and Table 2 presents the results of the multivariate analysis.

Table 1. Conditional probabilities of Russia's involvement in militarized disputes, 1992–2010

*P < 0.05; **P < 0.01; ***P < 0.001 (two-tailed test).

^a To facilitate reading, probabilities have been multiplied by 1000.

^b The Polity IV project does not code countries with less than 500,000 inhabitants; cases of foreign ‘interruption’ are treated as missing.

Table 2. Logit model: Russia's military escalation decisions, 1992–2010

*P < 0.05; **P < 0.01; ***P < 0.001 (two-tailed test).

As is clearly evident from the figures in Table 1, the main results are mostly consistent with our hypotheses. Nevertheless, hypotheses are derived from theories of international relations that are partly complementary and partly competitive. Therefore, although international variables operate with one significant exception, domestic variables necessitate some qualifications.

The role of relative power (RP) is very important for explaining the risk of Russia's involvement in a military dispute. The probability of a military escalation largely increases when the power difference is small and decreases when it is large. When the power difference is small, there is an increase in the probability of military escalation from 0.023 (unconditional probability – p _u) to 0.103 (conditional probability – p _c); in other words, when the power difference between Russia and the other states is less than 3, the likelihood of Moscow's military involvement increases almost five times. This result is highly statistically significant (Z score: 7.45, p < 0.001). Conversely, when the power difference is very large (Russia's power is more than 10 times as great as its adversary), the probability of a military dispute decreases sharply. In this situation, the probability of Russia's MID involvement shifts from 0.023 to 0.015, with a significant decline in risk (Z score: −2.94, p < 0.01).

Considering the role of power, the results of our analysis seem consistent with hypothesis 1b, which affirms that a conflict is more likely when there is not such a great power gap between the contending states: in this case, mutual miscalculation about the outcome of a conflict drives both states to decide not to back down. The idea that a balanced distribution of power is a source of peace is not confirmed by Russia's military behaviour. As the rationalist theory of war states, Moscow's risk of military escalation increases dramatically when the adversaries are not so weak as to decide to capitulate without fighting. As Geoffrey Blainey put it (Reference Blainey and :1988: 114): ‘Indeed one can almost suggest that war is usually the outcome of a diplomatic crisis which cannot be solved because both sides have conflicting estimates of their bargaining power’. This is not the case when there is a situation of preponderance and Russian leaders are no exception.

The second international variable linked to power distribution – alliance (ALL) – does not work as well as RP. It works in the opposite direction vis-a-vis our expectations and has no statistical significance. Our hypothesis (hypothesis 2) was that – adhering to a logic of external balancing – the presence of a defence pact with a third country by the target state would deter Moscow's military intervention or at least reduce its frequency. The data are not consistent with this expectation. The direction of the relation is positive, which means that Russia's likelihood of MID involvement is greater with countries that have a defence pact with a third country and not the other way around. This can be explained in three ways:

1. (1) External balancing is not considered credible by Moscow's decision makers;

2. (2) The result is produced by a selection bias, that is, states that have good reasons to be involved in a dispute with Russia are more motivated to enter into an alliance system;

3. (3) Russia is more conflict prone with states that have an alliance because it wants to prevent the formation of future alliances, making them not worth the risk.

In any case, the All variable is not statistically significant in the bivariate analysis; thus, we can say that Russia's military decisions do not seem very affected by this dimension of power distribution.Footnote ²⁵

The third international variable considered is the territorial salience of the dispute. We coded this variable in a very simple way: whether the disputant state belongs or does not belong to the post-Soviet space (PSS). PSS, together with RP, is the best predictor of Russia's military behaviour. The probability of Russia's MID involvement shifts from a p _u of 0.023 to a p _c of 0.090 when we consider only dyads including states that belong to the PSS. This means a risk of conflict four times greater. The result is highly statistically significant (Z score: 7.36, p < 0.001). These figures are consistent with our hypothesis 3. Although the factor of geographic proximity can be deemed as a ‘structural modifier’ of the capacity of power projection (Ripsman et al., Reference Ripsman, Taliaferro and Lobell2016: 40), the salience of the post-Soviet space ‘as such’ to Russia is a very compelling argument. Countries belonging to the PSS – as stated in the third section – have both material and symbolic elements of salience: they are a sign of past greatness; can play a role as a buffer zone; have economic/energy importance; and are inhabited by Russian speaking people. If we take into account Paul Hensel's list of factors that determine the salience of a land dispute between two states, we find that they are all present in the case of Russian interventions in the PSS. Hensel states that the salience of a territorialFootnote ²⁶ dispute is determined by six elements (Hensel et al., Reference Hensel, McLaughlin Mitchell, Sowers and Thyne2008: 130):

1. (1) Territory is considered a homeland territory;

2. (2) Territory is inhabited by a permanent population;

3. (3) Territory previously belonged to the claimant state;

4. (4) Territory may contain important natural resources;

5. (5) Territory has an important economic or a strategic position; and

6. (6) Groups living on the territory have some sort of an ethnic/cultural relationship with the claimant state.

At first glance, it is evident that all conditions but the first are present in the relations among Russia and its near abroad.Footnote ²⁷ Consequently, it is not surprising to find that the PSS variable plays such a crucial role in Moscow's decision to escalate the level of a dispute.

The reactions of a state to international stimuli are affected/mediated by domestic factors. Accordingly, we now have to consider the impact of the two domestic variables that we have selected from the broad literature on Russia's foreign policy, to test their impact on military behaviour.

The first factor, the level of democracy/autocracy, was tested in two different ways: first, we analysed the impact of the change in Russia's level of democracy/autocracy on its military behaviour, not considering the nature of the opponent state's political regime (hypothesis 4a). In this case, the idea that an increase in the level of Russian authoritarianism (Pol1) increases the conflict-proneness of Moscow is consistent with the empirical result. An increase in the level of autocracy (or a decrease in the level of democracy) increases the probability of Russia's MID involvement from a p _u of 0.023 to a p _c of 0.037. An authoritarian Russia is 1.5 times more likely to be involved in a military dispute with another state (the latter's political regime notwithstanding). These data are statistically significant (Z score: 3.38, p < 0.001).

More controversial are the data regarding our test of the hypothesis derived from the democratic peace theory (hypothesis 4b). In this case, Moscow's military behaviour seems to contradict the dominant literature that affirms that democratic dyads are less conflict-prone than non-democratic or mixed dyads. In the case of Russia, the probability of conflict is higher in the case of democratic or mixed dyads and lower when non-democratic dyads are considered (Pol2).Footnote ²⁸ Although the data about democratic and non-democratic dyads have no statistical significance, the finding is interesting because it highlights that the theory of ‘democratic contagion’ is more consistent with Russia's international behaviour than democratic peace theory: democratic spill over endangers regime survival; thus, Russia is more likely to target democratic states than non-democratic states (Ambrosio, Reference Ambrosio2009).Footnote ²⁹ This happens because Russia has an interest in actively resisting or undermining regional democratic promotion that may spill beyond the Russian borders. During the waves of colour revolutions across the post-Soviet space between 2005 and 2008, Russia officially condemned them as a ‘regime overthrown’ promoted by the West, and the Kremlin adopted several tools to achieve authoritarian resistance to such social change (Ambrosio, Reference Ambrosio2009). At the same time, Russia bolstered autocratic regimes in several post-Soviet states (Vanderhill, Reference Vanderhill2013) and promoted a global agenda parallel to that of the West (Bader et al., Reference Bader, Grävingholt and Kästner2010; Dias and Freire, Reference Dias, Freire, Çakmak and Özçelik2019).

The last domestic variable tested focuses on regime stability. Studies on Russia's foreign policy have produced contradictory evidence on this point. As we have seen in section two, some studies stress the depressing impact of regime instability on international behaviour (low profile foreign policy hypothesis – hypothesis 5a), while others stress evidence of more assertive foreign policy deriving from domestic instability (diversionary war hypothesis – hypothesis 5b).

Empirical data on regime vulnerability (RV) clearly show that the diversionary hypothesis is more robust in the case of Russia. An intensification of regime instability increases the probability of Russia's MID involvement from 0.023 to 0.040. Conversely, a rise in regime stability decreases the risk of military involvement from 0.023 to 0.009: when Russia's regime is stable, the likelihood of MID involvement is 2.5 times lower. The data on high and low RVs are all statistically significant.

The bivariate analysis clearly shows that relative power (RP) plays a decisive role in explaining the likelihood of Russia's MID involvement. A similar crucial role is played by the nature of the bone of contention: when a dispute involves a former Soviet state (PSS), the risk of a conflict with Moscow rises dramatically. Both the level of autocracy (Pol1) and domestic instability positively affect Russia's military behaviour, prompting a more aggressive posture. The democratic nature of target states (Pol2) does not seem to restrain Moscow's military behaviour: anxious about a possible democratic contagion, Moscow seems more prone to quarrel with democratic states.

Now, we shift to a multivariate analysis, where all the variables are considered jointly. Due to missing data on the level of democracy in countries below 500,000 inhabitants and in countries under foreign occupation, the multivariate analysis (logistic regression) was applied to a sample of 3048 dyads and 80 MIDs.Footnote ³⁰ The results are presented in Table 2.

The impact of relative power is confirmed for both direction and weight. Even when all the variables are considered as acting jointly, the power difference between Russia and the target states remains critical for explaining military escalation decisions. An increase in the power difference (a shift from a small power difference to a large power difference) reduces the probability of Russia MID involvement in a significant way. More to the point, a large RP difference reduces the likelihood of a military escalation by 64%.Footnote ³¹ RP's impact is highly statistically significant (p < 0.001). When compared to the bivariate results, these data demonstrate the important effect of domestic variables on the RP role in Russia's military behaviour. When all the factors are not considered jointly, the shift from a small to a large RP gap reduces the likelihood of MID involvement by approximately 35%. These results are consistent with the neoclassical realist approach, which affirms that to understand a country's reaction to international stimuli, we have to consider also the modifying role of unit-level variables.Footnote ³² In this case, domestic variables mitigate in a significant way the most negative effect of power gap.

The multivariate analysis confirms the eccentric role played by the alliance variable (All), which maintains a positive sign and a low statistical significance (p < 0.10). These data deserve further investigation to test which of the alternative explanations advanced in the bivariate analysis can shed some light on this apparently contradictory result (Moscow's indifference towards alliance defence pacts, selection bias, a ‘teach a lesson’ strategy).

The role of the territorial salience of the dispute is largely confirmed by our multivariate analysis. The logit coefficient for the PSS variable is positive, as expected, and statistically significant (p < 0.001). The involvement of Russia in the post-Soviet space remains one of the best predictors of conflictual behaviour. An increase in the logit coefficient dramatically increases the event modelled (Russia's MID involvement). A dispute with a state belonging to the near abroad increases the risk of military confrontation by 100[Exp(B) – 1] = 1200%. In this case, as is the case for RP, other factors significantly affect the impact of the variable under observation (PSS, when considered alone, produced a change of 291%). Thus, RP and unit-level variables seem to have an amplifying effect on the impact of territorial salience on Russia's dispute decisions.

By analysing the three domestic variables included in our model (Pol1, Pol2, and RV), the bivariate results are partially confirmed. Pol1, although operating in the expected direction, is not very statistically significant (p < 0.10). Nevertheless, the hypothesis that in the case of Russia's military behaviour the ‘democratic contagion’ theory works better than democratic peace theory is confirmed. A shift from non-democratic dyads to democratic dyads (Pol2) increases the probability of Russia's MID involvement by 100[Exp(B) – 1] = 120%. These data are statistically significant (p < 0.01).

The last domestic variable analysed is regime vulnerability. Logistic regression produced data consistent with the diversionary hypothesis. The logit coefficient for RV was positive, meaning that domestic instability makes the event modelled more likely. When Russia is experiencing regime vulnerability, the risk of MID involvement increases. In particular, when RV is high, the risk that Russia will resort to an external military confrontation increases by 100[Exp(B) – 1] = 116%. RV has a more amplifying effect when considered together with the other variables: in the bivariate analysis, the impact of a high RV was to increase the probability of Russia's MID involvement by 74%. This means that a diversionary logic cannot be considered a good explanation without reference to power balancing considerations.Footnote ³³

In conclusion, the multivariate analysis is consistent with the bivariate analysis, and this fact clearly hints at the robustness of our empirical results. Another factor that unmistakably emerges is that unit-level variables tend to significantly affect states' external behaviour, amplifying (overreaction) or mitigating (under-balancing) conflict-proneness, as expected by neoclassical realism (Snyder, Reference Snyder1991; Schweller, Reference Schweller2004). The empirical findings are summarized in Table 3.

Table 3. Probability of Russia's military escalation decisions