Good evening everyone,

Last time we met we looked at how realism applied to the study of international security. Ben discussed that many theories of international relations generally are theories of international security due to the centrality of security concerns to states and we continue that journey today. Although the title of today's lecture is 'Alliances and Balancing', I will also, if I get time, talk about Liberialism and Constructivism in the context of their predictions regarding alliances and balancing because we didn't get to cover those theories last week.

A discussion of alliances generally talk about two questions - why do states ally with one another (i.e what causes alliances) and why do they endure or break-down. Alliances are also hypothesised to both increase and decrease the probability of war. Do alliances cause wars? Do they cause states to act aggressively? Do they drag major powers into costly and peripheral conflicts? These are important contemporary questions, as the survival of NATO and SEATO despite the collapse of Russia as a common threat is surprising to some commentators.

Realism is a handy departure point, because the relationship between alliances and balancing according to many realist scholars such as Waltz and Walt is fairly straightforward. in addition, realism make quite specific predictions about what causes alliances to form, what causes them to dissolve, and the circumstances under which they are likely to lead to war. According to realists such as Kenneth Waltz, states use alliances as a means to balance capabilities in the international system. More specifically, states use alliances to balance the capabilities of a preponderant actor in the world system when they are unable to balance them internally (i.e build their own military forces) or the costs of balancing are higher than the costs of aligning with other countries. The difference between internal and external balancing is me building the guns and tanks to match you guns and tanks and me joining forces with another country to equal out, or exceeed, the guns and tanks that you have. On the other hand, realists argue that the distribution of power, or the balance of power, causes states to ally with one another. Unbalanced power is threatening to everyone. We should be familiar with the logic from Mearshiemer's article. Because states cannot be 100% certain about the intentions of other states, they act check the emergence of hegemons or preponderant powers. In other words, when it looks like one state is gaining an ascendancy, other states band together, they ally, to balance its power. They aggregate their military capabilities. Alliance patterns are broadly predictable by looking at the concentrations of power in the international system. So in this way, the distribution of capabilities in a system is a cause of alliance patterns.

To summarise then, a key argument of realist scholarship is that states ally with other states as a means to balance capabilities and ensure their security. Balancing can be achieved through one of two means, internally and externally. When internal balancing is not possible, or is has less utility than external balancing, states will band together to check the power of a dominant state. There is an important distinction here. Structural realists such as Waltz argue that states balance capabilities, regardless of who has them.

Realists use the example of NATO and the Warsaw Pact. States in Western Europe and the United States used a combination of Internal and External balancing to create a balance of power and improve their security. States in Eastern Europe allied with the Soviet Union

Realists also make predictions about when alliances are likely to endure, and when they are likely to break down. As we might expect, when the common threat that caused the alliance to form in the first place dissapears, so too does the reason for allying, causing the alliance to break down.

Moving onto the first reading, realism also has something to say about when alliances are likely to lead to war and when they are not. Snyder and Christiansen argued that when offensive capabilities are perceived to have the advantage, alliances act like chain gangs. Recall the distinction made by Robert Jervis in last week's readings between offensive and defensive military capabilities. When one country in the alliance goes to war, others jump off the precipice with it. The logic behind this argument is that, when offense is perceived to have the advantage, states must act quickly (even pre-emptively) because if they don't their ally might be hastily defeated, altering the balance of power and lowering the probability that the alliance can prevail in a conflict. Snyder and Christiansen argue that a perception of offensive advantage, shaped by the experience of German-French wars in the 1870s, explains why European states jumped into war in 1914.

When defence is perceived to have the advantage, Snyder and Christainsen argue that we are likely to see more buck-passing between allies and a greater hesitancy to go to war. Because offensive states will have to invest proportionally more into their victory and other states are likely to be able to hold their own without external help, states in the Alliance can afford to watch on and allow costs to absorb before jumping in themselves.