What drives a state’s weapons acquisition strategy? States are often concerned about being cut off from their weapons suppliers when security interests diverge. As weapons production becomes increasingly globalized, however, international inputs are often unavoidable. To mitigate the risks of being cut off, states tend to source their weapons from foreign suppliers only when their security interests align. The success of this approach, however, depends on the challenges associated with securing alternative sources. In this article, I implement regression analysis, social network analysis, and process tracing to test my argument. Using multiple datasets, I measure security interest compatibility and asset specificity. The result confirms my hypotheses. Then, I use qualitative evidence from Taiwan and South Korea to conduct process tracing. Leveraging the 1969 Nixon Doctrine as an exogenous shock, I analyze their decisions to develop defense industries and surface combatants between the 1960s and 1980s. Diverging interests with the United States drove both states to pursue domestic production. However, the extent to which they could incorporate domestic components varied, reflecting the differing complexities of their respective programs. This article contributes to the literature by revisiting the security-autonomy tradeoff framework, offering new insights into the politics of armaments and their relationship with alliance politics. 

What determines a state’s priority when acquiring weapons? I argue that weapons acquisitions reflect a state’s effort to align its foreign policy with like-minded states. However, importing military equipment from foreign suppliers carries the risk of supply disruptions when interests diverge. To mitigate this risk, states procure weapons from suppliers with converging security interests or engage in domestic production when industrial conditions allow. To test this argument, I analyze the weapons acquisitions of Eastern and Central European (ECE) states from the end of the Cold War through multiple waves of NATO enlargement. These states were required to acquire adequate equipment before joining NATO. Consequently, states closely aligned with NATO members were more likely to procure the key Western equipment necessary for accession rather than acquiring or manufacturing Soviet-style products. I focus on command, control, and communications equipment, which was listed as a requirement for NATO accession. This article adopts a multi-method approach, employing social network analysis and process tracing. Using the SIPRI Arms Transfers Database and the Distribution of Military Capabilities Dataset (rDMC), the stochastic actor-oriented model (SAOM) demonstrates that interest compatibility influenced the acquisition decisions of new NATO member states. States aligning more closely with the West acquired a higher proportion of Western-style weapons, while those less aligned obtained more Soviet-style weapons. These efforts signaled new NATO members’ intention to reduce reliance on Russia and align with the West, reflecting a broader realignment of their foreign policies. A case study of Poland illustrates how the acquisition of key weapons and the incorporation of new defense concepts were integral to its decision to align with the West before NATO accession. This article contributes to the study of alliance politics by examining the role of military technology in NATO enlargement. It also provides insights into arms transfers, burden-sharing, and defense cooperation. 

What drives a state’s weapons acquisition strategy? States are often concerned about being cut off from their weapons suppliers when security interests diverge. As a result, they are strongly motivated to produce weapons domestically rather than rely on external sources. However, not all states can resolve this concern through import substitution. This article argues that a state's decision to make or buy weapons depends on both its relationship with major suppliers and its capacity to develop and produce weapons. States facing diverging interests but lacking sufficient defense industrial capabilities often initiate defense industrialization efforts to catch up. At the same time, they tend to maintain relationships with major suppliers to access technological input, to eventually replace those sources. However, when weapons programs become overly ambitious, dependence may persist. This article draws on archival evidence to examine how Japan, South Korea, and Taiwan developed new naval capabilities in the wake of the 1969 Nixon Doctrine. Specifically, it investigates Japan’s P-3C, South Korea’s FFK-1, and Taiwan’s PFG-1 programs. While Japan maintained its dependence on the US, given its strong relationship with the United States, South Korea and Taiwan launched indigenous programs to mitigate fears of abandonment. Taiwan, however, ultimately halted its plan for full domestic production due to doctrinal shifts and fiscal and technological constraints. In contrast, South Korea successfully completed the domestic production program and expanded its defense sectors.

Why does China send aircraft and ships to the Taiwan Strait despite its increasingly adverse international environment? Chinese military incursions into Taiwan's Air Defense Identification Zone (ADIZ) have occurred daily over the past few years. The routinized crossing of the Median Line in the Taiwan Strait has heightened the risk of miscalculations. However, it is puzzling why these operations persist. I argue that the motivations behind China's force demonstrations have international and domestic audiences. While China seeks to bolster its reputation for resolve on territorial issues, it could stimulate domestic pressures that generate demands for more aggressive military operations. This could effectively tie China’s hands even when escalation is undesirable. To test these arguments, I use an original dataset of China’s daily military operations in the Taiwan Strait spanning from 2016 to 2024. This dataset includes the quantities and types of Chinese aircraft detected by Taiwan and Japan. Additionally, I collected information about US official visits and China's domestic protests. With the granular dataset, the Poisson models reveal that China's military operations are positively associated with US support for Taiwan and the scale of domestic protests. However, when military operations aiming at deterring the US overlap with domestic protests, China scales down its military operations in the Taiwan Strait. This article contributes to ongoing discussions about military coercion, the domestic politics of military operations, and the US-China great power competition. 

Why do states form strategic partnerships—a non-binding agreement on long-term interstate cooperation? Since the 1990s, strategic partnerships have emerged as a new diplomatic instrument that allows states to collaborate on multiple areas, including economic, diplomatic, security, and sociocultural issues. While partner states make explicit their intent of comprehensive and enduring cooperation, their partnerships are often announced through joint declarations and official statements as a form of low-degree legalization. Why do states choose such a low-cost and less credible method for mutual collaboration? In this article, we argue that strategic partnerships serve as a promise short of formal commitments. Although conventional wisdom suggests that states in pursuit of cooperation should increase credibility with costly signaling, they also use strategic partnerships to deal with uncertainty. First, with the announcement of strategic partnerships, partner states can strengthen their reputation of cooperation. Second, the low costs of such partnerships initiate a process in which partner states can learn about the impact of their cooperation over time. Third, their non-binding agreements allow state leaders to build domestic support without incurring audience costs. In this regard, strategic partnerships are more likely to facilitate compromise and thus mutual cooperation between states with different interests and values. Authoritarian regimes, compared to democracies, could favor this form of cooperation to reward winning coalitions with ease. To test our argument, we collect an original dataset of strategic partnerships that contains 1400 records of global partnership agreements from 1990 to 2020. With the dataset, we implement Temporal Exponential Random Graph Models (TERGMs) and find that authoritarian states are more likely to sign partnership agreements than democratic states. Our article makes a contribution to the literature on international cooperation by adopting a multi-method approach to the study of strategic partnerships, as well as broadening our understanding of authoritarian cooperation in the era of great power competition. 

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