Why Weaker States Quit Asymmetrical Alliances Under Common External Threat?

Alliance dissolution, which means alliances end through opportunistic abrogationby members, is not equivalent to alliance termination. In the past several decades, thequestions of why alliances dissolve have received much less attention than the questionsof why alliances form. This dissertation however focuses attention on why weaker statesquit asymmetrical defensive alliances while the external threats which the alliancesinitially targeted against still exist.The dissertation then develops a bi-variable theory explaining how self-helpcapability and strategic discrepancy can cause alliance to dissolve. The theory positsthat alliance costs the weaker states should bear is a function of alliance internalstrategic discrepancy, the greater the strategic discrepancy is, the more costs the weakerstates would pay. Meanwhile, alliance benefits which the weaker states can gain fromthe alliances is determined by the weaker states’ self-help capability, the stronger theweaker states are, the less they can benefit from the alliances. Therefore, when therecomes up significant strategic discrepancy in alliances, the weaker states need tosacrifice core interests to maintain alliances. If at that time the weaker states are strongenough, which means the alliances are not matters of life and death, the weaker stateswill quit the alliances.Furthermore, the dissertation analyzes how alliance costs and benefits influencealliances’ utility using indifference curves, and explain why significant strategicdiscrepancy and strong self-help capability are two necessary conditions to causealliances to dissolve.In order to test the causal mechanism of the theory of this dissertation specifically,the research firstly examines the Sino-Soviet alliance from1950to1967and carry outintra-case comparative study. The intra-case comparative studies show that from1950to1957, there’s no significant strategic discrepancy in the Sino-Soviet alliance, nor didChina possess sufficient self-help capability, then the Sino-Soviet alliance persisted.Though there’s noticeable strategic discrepancy in the Sino-Soviet alliance from1958to1966, yet China still had no ability to defend itself at that period, the Sino-Sovietalliance also persisted. However, when China gained the ability to defend itself after 1967, the Sino-Soviet alliance dissolved under the impact of strategic discrepancyinside the alliance. These findings support the theory this dissertation develops.Secondly, the dissertation tests the theory against other alliances, such as theUS-South Korean alliance from2001to2008, the Franco-American alliance from1958to1967, and the Anglo-American alliance after1957, so as to show the universality ofthe theory. The results of the case study support the theory once again.Finally, The dissertation then tests four research hypotheses derived from thetheory based on Cox proportional hazards model. The results show that both self-helpcapability and strategic discrepancy have conditional influence on alliance dissolution.If the self-help capability of the weaker states in the asymmetrical alliances is strongenough, there’ll be positive correlation between strategic discrepancy and alliancedissolution; otherwise, there’ll be no significant correlation. Meanwhile, if the strategicdiscrepancy is noticeable enough, there’ll be positive correlation between self-helpcapability of the weaker states and alliance dissolution; otherwise, there’ll be nosignificant correlation. These findings from statistical analysis also support the alliancedissolution theory this study develops.