Deterrence theory
Deterrence theory refers to the scholarship and practice of how threats of using force by one party can convince another party to refrain from initiating some other course of action.[1] The topic gained increased prominence as a military strategy during the Cold War with regard to the use of nuclear weapons and is related to but distinct from the concept of mutual assured destruction, according to which a full-scale nuclear attack on a power with second-strike capability would devastate both parties. The central problem of deterrence revolves around how to credibly threaten military action or nuclear punishment on the adversary despite its costs to the deterrer.[2] Deterrence in an international relations context is the application of deterrence theory to avoid conflict.
This article is about Deterrent in peace and conflict studies and nuclear weapons. For legal theory of justice, see Deterrence (penology).
Deterrence is widely defined as any use of threats (implicit or explicit) or limited force intended to dissuade an actor from taking an action (i.e. maintain the status quo).[3][4] Deterrence is unlike compellence, which is the attempt to get an actor (such as a state) to take an action (i.e. alter the status quo).[5][6][4] Both are forms of coercion. Compellence has been characterized as harder to successfully implement than deterrence.[6][7] Deterrence also tends to be distinguished from defense or the use of full force in wartime.[3]
Deterrence is most likely to be successful when a prospective attacker believes that the probability of success is low and the costs of attack are high.[8] Central problems of deterrence include the credible communication of threats[9][4] and assurance.[10] Deterrence does not necessarily require military superiority.[11][12]
"General deterrence" is considered successful when an actor who might otherwise take an action refrains from doing so due to the consequences that the deterrer is perceived likely to take.[13] "Immediate deterrence" is considered successful when an actor seriously contemplating immediate military force or action refrains from doing so.[13] Scholars distinguish between "extended deterrence" (the protection of allies) and "direct deterrence" (protection of oneself).[12][14] Rational deterrence theory holds that an attacker will be deterred if they believe that:[15]
This model is frequently simplified in game-theoretic terms as:
History[edit]
By November 1945 general Curtis LeMay, who led American air raids on Japan during World War II, was thinking about how the next war would be fought. He said in a speech that month to the Ohio Society of New York that since "No air attack, once it is launched, can be completely stopped", his country needed an air force that could immediately retaliate: "If we are prepared it may never come. It is not immediately conceivable that any nation will dare to attack us if we are prepared".[16]
Most of the innovative work on deterrence theory occurred from the late 1940s to mid-1960s.[17] Historically, scholarship on deterrence has tended to focus on nuclear deterrence.[18] Since the end of the Cold War, there has been an extension of deterrence scholarship to areas that are not specifically about nuclear weapons.[4]
NATO was founded 1949 with a role including deterring aggression.[19]
A distinction is sometimes made between nuclear deterrence and "conventional deterrence."[20][21][22][23]
The two most prominent deterrent strategies are "denial" (denying the attacker the benefits of attack) and "punishment" (inflicting costs on the attacker).[11]
Lesson of Munich, where appeasement failed, contributes to deterrence theory. In the words of scholars Frederik Logevall and Kenneth Osgood, "Munich and appeasement have become among the dirtiest words in American politics, synonymous with naivete and weakness, and signifying a craven willingness to barter away the nation's vital interests for empty promises." They claimed that the success of US foreign policy often depends upon a president withstanding "the inevitable charges of appeasement that accompany any decision to negotiate with hostile powers.[24]
Since the early 2000s, there has been an increased focus on cyber deterrence. Cyber deterrence has two meanings:[61]
Scholars have debated how cyber capabilities alter traditional understandings of deterrence, given that it may be harder to attribute responsibility for cyber attacks, the barriers to entry may be lower, the risks and costs may be lower for actors who conduct cyber attacks, it may be harder to signal and interpret intentions, the advantage of offense over defense, and weak actors and non-state actors can develop considerable cyber capabilities.[61][62][63][64] Scholars have also debated the feasibility of launching highly damaging cyber attacks and engaging in destructive cyber warfare, with most scholars expressing skepticism that cyber capabilities have enhanced the ability of states to launch highly destructive attacks.[65][66][67] The most prominent cyber attack to date is the Stuxnet attack on Iran's nuclear program.[65][66] By 2019, the only publicly acknowledged case of a cyber attack causing a power outage was the 2015 Ukraine power grid hack.[68]
There are various ways to engage in cyber deterrence:[61][62][63]
There is a risk of unintended escalation in cyberspace due to difficulties in discerning the intent of attackers,[72][73] and complexities in state-hacker relationships.[74] According to political scientists Joseph Brown and Tanisha Fazal, states frequently neither confirm nor deny responsibility for cyber operations so that they can avoid the escalatory risks (that come with public credit) while also signaling that they have cyber capabilities and resolve (which can be achieved if intelligence agencies and governments believe they were responsible).[71]
According to Lennart Maschmeyer, cyber weapons have limited coercive effectiveness due to a trilemma "whereby speed, intensity, and control are negatively correlated. These constraints pose a trilemma for actors because a gain in one variable tends to produce losses across the other two variables."[75]
Intrawar deterrence[edit]
Intrawar deterrence is deterrence within a war context. It means that war has broken out but actors still seek to deter certain forms of behavior. In the words of Caitlin Talmadge, "intra-war deterrence failures... can be thought of as causing wars to get worse in some way."[76] Examples of intrawar deterrence include deterring adversaries from resorting to nuclear, chemical and biological weapons attacks or attacking civilian populations indiscriminately.[77] Broadly, it involves any prevention of escalation.[78]