The central premise in Nested Security is that so-called “civil” wars are rarely confined to state borders, but instead feature a range of trans- or inter-state actors—including trans-border kin groups, long-distance diasporas, foreign governments, international organizations, and other cross-border networks. The most critical actors are concentrated at the regional level; the immediate conflict environment plays a vital role in shaping domestic struggles. Examples include the cross-border arms flows from Albania that built the Kosovar Albanian insurgency in the 1990s and the network of safe havens in the bordering Indian state of Tamil Nadu, which permitted the Tamil Tigers to wage a decades-long separatist war in Sri Lanka. Complicating matters still further, regional conflicts are often embedded in wider conflict processes at the systemic level. During the Cold War, for instance, the Palestinian conflict was embedded in a wider Arab-Israeli regional conflict, which in turn was embedded in the US-Soviet struggle over dominance of the region. That regional and systemic factors jointly impact communal conflict on the ground is evident in present-day Kosovo, where decades-long efforts to integrate the Serb minority into the state have been stymied by rivalry between Belgrade and Pristina—a rivalry exacerbated by a periodic US-Russian struggle over influence in the Balkans.

That communal conflicts are nested in wider conflict processes is hardly a novel observation (Sahleyan Reference Salehyan2009; Lake and Rothschild 1996; Mylonas Reference Mylonas2012; Forsberg Reference Forsberg2014). However, the wider nestedness of civil conflicts has not been adequately conceptualized in the peace-building literature, which focuses disproportionately on domestic mechanisms of conflict management such as power-sharing arrangements (Sisk Reference Sisk1996) and electoral engineering (Reilly Reference Reilly2001). Nested security encourages scholars to use a wider analytical lens to attend to drivers of conflict that extend well beyond the domestic arena. The argument in a nutshell is that effective mediation requires brokering or neutralizing these wider conflict pressures emanating from the regional and/or systemic levels—a process I call exogenous stabilization. The role of major powers in creating this environment is a theme that runs through the book. In a series of clustered case studies, I show that soft power conflict management succeeds when the mediator de-triangulates kin state-minority-majority conflicts, brokering attractive side deals with each party. The book shows through a series of clustered case comparisons that the effectiveness of the League of Nations minority protection system (MPS) and the post-Cold War European Union (EU)/Organization for Security and Co-operation in Europe (OSCE) High Commissioner on National Minorities (HCNM) system has hinged to a great extent on major power assistance in achieving the right balance between state center and minority at every point. The case studies further suggest that a stabilized environment may not only be a necessary, but also a sufficient, condition for effective third-party conflict management.

In three incisive commentaries, Robert Jervis, Zsuzsa Csergő, and Harris Mylonas acknowledge the outsized impact external conflict processes have on civil conflicts. Indeed, Mylonas (Reference Mylonas2012) has shown that rival neighboring states can escalate ethnic tensions in the target state. Here, Mylonas writes that the international system, particularly its polarity and actions of great powers, is also likely to affect the shape of civil conflict management. He further argues that regional integration schemes might be used to achieve exogenous stabilization in the absence of great power engagement; regional organizations such as the EU and OSCE can step into the breach insofar as great powers retreat from their commitments to conflict management. Although possible in principle, I would argue that such schemes nearly always require major power backstopping to achieve success. The League of Nations offers an early example of this. In the early 1920s, the new and enlarged states of Poland, Czechoslovakia, and Romania reduced the privileges enjoyed by formerly dominant German and Hungarian minorities, often in violation of their minority treaties. The League’s Minority Protection System (MPS) failed to respond adequately to minority appeals for redress for the turbulent period prior to 1919–1923. Great power intervention helped to turn this around. The British and US powers played a vital role, sometimes through technical and diplomatic channels, to stabilize bilateral and multilateral relations in Central and Eastern Europe. For the German minority in Czechoslovakia, the 1925 Locarno Treaty created incentives for Prague and Berlin to normalize diplomatic relations, paving the way for a decade of interethnic governance in Czechoslovakia. Likewise, the MPS was able to pursue more effective mediation of minority conflicts in Romania only after Italy, Austria, and Germany pushed Budapest to make peace with Bucharest, leading to successful resolution of an outstanding land appropriation case in 1930. Predictably, these minority conflicts flared up again in the late 1930s when Germany and Hungary empowered separatism in Romania and Czechoslovakia, later annexing their territory.

Great powers continue to play a vital role in conflict management in Central and Eastern Europe today. In 1993, the Estonian parliament passed the “Alien Act” in a bid to exclude Russian speakers from citizenship and encourage outmigration, leading Russian separatists in Narva and Silläema to organize referenda for independence. To de-escalate tensions, the HCNM, the US ambassador to Estonia, and officials in the Clinton administration worked behind the scenes to dissuade the Kremlin from encouraging separatist aspirations of Russian speakers in the border towns of Narva and Silläema. The mix of sticks and carrots offered to Moscow persuaded the government to scale back their support for separatists. Meanwhile, promises of North Atlantic Treaty Organization (NATO) and EU membership convinced the Baltic governments to liberalize their citizenship laws at the behest of the High Commissioner.

Great power involvement was also critical to containing the short-lived war in Macedonia in 2001. When remnants of the Kosovo Liberation Army (KLA) crossed the border to incite bloody clashes in northwest Macedonia, US and NATO officials met separately with Albanian separatists and strong-armed them into disbanding with promises of amnesty for fighters and a generous power-sharing arrangement. At the same time, NATO, the USA, and the EU convinced Macedonian leaders to agree to and implement the Ohrid Peace Agreement (OPA), linking implementation of the OPA to the country’s eventual accession to the EU and NATO.

Csergő and Mylonas both argue, however, that non-state actors play a greater role in de-escalating minority-majority conflicts than the model allows. Csergő argues that the nested security theory underestimates the independent role of domestic actors and institutions in creating and reinforcing the conditions of peace, even as turbulence in the region increases (Csergő and Regelmann Reference Csergő and Regelmann2017). She notes that domestic actors were vital to the success of the OPA over and above the incentives for compliance provided by the USA, NATO, and EU. She further contends that domestic actors can resist the disruptive effects of outside actors. Here, she cites the example of ethnic Hungarian parties in Slovakia and Romania, which have resisted attempts by the Fidesz-led Hungarian government to coopt their interest representation. In the Baltics, meanwhile, the pro-integration policies of the Estonian and Latvian governments appear to have increased the integration of Russian-speakers, even in the face of rising Russian nationalism and revisionist campaigns. Csergő recommends extending the model to capture the interactive effects of domestic networks on the ground that are activated by efforts by third parties to produce the condition of nested ethnic peace. Her advice is well-taken, as a study of cross-border social networks promises to reveal the micro-foundations of exogenous stabilization, increasing the validity of the model’s causal hypotheses.

While this modification would doubtless improve the descriptive accuracy of the model, it is unclear whether it would change the model’s predictions. The cases cited by Csergő actually make the point that domestic players were secondary players in the production and maintenance of ethnic peace. Csergő herself observes that the Estonian conflict de-escalated in the 1990s due to EU/NATO membership conditionality and Russian weakness—factors that pertain to the international level. These conditions strongly favor minority integration—indeed, the Russian Harmony Party in Latvia and multi-ethnic Center Party in Estonia actually formed governing coalitions. Hence, the Baltic successes were predicated on the actions of major powers that exogenously stabilized the tiny countries.

The same pattern holds for the minority-majority conflicts elsewhere in Central and Eastern Europe. With minorities oriented toward transatlantic organizations (Birnir Reference Birnir2007) and moderates on both sides empowered by the prospects of EU/NATO accession (Vachudova Reference Vachudova2005), western governments have succeeded in nesting ethnic conflicts in a stable external environment. However, these conditions are subject to continual change. In recent years, the clientelist regime of Viktor Orbán succeeded in coopting the main Hungarian party in Romania (UDMR) (Pogonyi Reference Pogonyi2017). Hungary’s nationalist rhetoric has occasionally provoked rebukes by the Romanian government. Meanwhile, a newer, pro-Fidesz party is coming closer to beating its moderate rival in Slovakia. This has so far failed to translate into escalating minority demands in either country, but the history of the region warns of the difficulty of maintaining ethnic calm in the midst of churning bilateral relations.

In today’s Europe, minority-majority relations have become unnested along the periphery of the EU and NATO. Mylonas’ recommendation that regional organizations serve as a mechanism forde-escalating communal tensions is a good one, but what of conflicts that lie just beyond their remit? A revisionist Russia is at least partly to blame for a five-year hot war over Russian minorities in eastern Ukraine, producing thousands of casualties. In the Caucasus, tensions between Azerbaijan and Armenia recently became bloody for the first time in two decades. In the Balkans, Serbian minority leaders in Kosovo and Bosnia continue to undermine their state governments; the leadership of Republika Srpska has worked to block Bosnia’s membership in NATO. Tensions have flared in Ireland over the future location of the EU border following Brexit. In Central Europe, Hungary has vowed to veto Ukraine’s accession to NATO over a new language law that impacts ethnic Hungarians in western Ukraine. What this suggests is that ethnic peace tends to come unglued along the contact points of security regimes, suggesting a need for bridging mechanisms to cover the geographical gaps and overlap between regional organizations tasked with managing ethnic tensions.

On February 21, 2017 the OSCE Secretary General declared in a briefing to the United Nations Security Council Open Debate that the Ukrainian war “marked the return of geopolitics on the OSCE agenda and it is challenging our model of co-operation. Inter-state relations are now more than ever before governed by a zero-sum mentality that we hoped we had left behind.”Footnote ¹ With the logic of geopolitics on the rise, and the USA retreating from European security architecture, we may soon be testing the limits of soft power conflict management in the absence of committed major power backing.