For my research theory I am studying the proposed United States/Mexico border wall because I want to know if this physical barrier will lessen illegal immigration, drug importation, and terrorist access so that readers understand how a physical border wall will improve United States national security.  The basic idea of deterrence theory is that an actor will avoid conflict if there is a strong enough deterrent. I chose to use deterrence theory to answer my research question because it is a substantive theory that answers both the individual and group actors response to various deterrences. Substantive theory is a “theory about a substantive issue or phenomena…Usually, the function of such a theory is both to describe and to explain; an explanatory theory is one which not only describes but also explains the phenomena of a substantive interest” (Punch 2016, 66).  “Deterrence is the use of a threat (explicit or not) by one party in an attempt to convince another party not to upset the status quo” (Quackenbush 2010, 60).   In order to understand how deterrence theory works today, it is important to know how the theory was conceptualized.  Although it is arguable that deterrence theory has been around since humans formed villages and protected themselves from other tribes, the earliest written reference that I was able to find in regards to deterrence theory was from 1764.  The deterrence theories we reference today are conceptualized from classical criminological theory.  The idea behind classical theory is “that punishments should be swift, certain, and proportionate to the crime in order to appro­priately deter individuals from violating the law” (Tomlinson 2016, 33). In 1764 Cesare Beccaria, an Italian economist and philosopher wrote “An Essay on Crimes and Punishments” (Tomlinson 2016, 33).  Beccaria argued that people make decisions based on what brings them either happiness or sadness-if committing crime made them happy then they would continue to commit crime unless they were successfully deterred from doing so (Tomlinson 2016, 33).  Then, in 1781, an English philosopher and social reformer, Jeremy Bentham, wrote “An Introduction to the Principles of Morals and Legislation (Introduction to the Principles)” (Tomlinson 2016, 33).  Bentham’s writing was more broad, and essentially stated that people would make rational decisions.  Bentham is considered the “forerunner to modern rational choice theory” (Tomlinson 2016, 33).  This is important because deterrence theory “assumes that potential offenders are rational agents capable of taking into consideration the consequences of their actions” (Lee 2017, 5).  The point being that the only way you could deter someone from committing a crime would be if they were able to understand and care about the adverse consequences they could face from committing the aforementioned crime.  This is why individuals who are not found mentally competent receive care in a mental institution instead of jail time as penance for their crimes.  In the 1970s deterrence theory was revitalized by economists and criminologists using it as both an explanation for why people commit crimes and as a solution to crime (Tomlinson 2016, 33). An alternative idea to to the theory mentioned above is that the first wave of deterrence theory wasn’t developed “until after World War II, as scholars such as Brodie, Wolfers, and Viner grasped the strategic implications of nuclear weapons.  However, at this stage, deterrence ideas had relatively little impact on policy and thy lacked the systematization and richness of” later improvements (Lupovici 2010, 706).  According to this theory, another iteration of deterrence theory emerged in the late 1950s that “incorporated game theory models (in particular the Chicken Game) into the study of deterrence.  The perceptions of this wave succeeded in becoming conventional wisdom”(Lupovici 2010, 706).  However, although this wave of thought reinvigorated deterrence theory, there was little evidence to support the hypothesis (Lupovici 2010, 706).   The scholars who agree that deterrence theory came about this way agree with Tomlinson that there was a revitalization, or  “third wave” in the 1970s which “revealed that deterrence theory needed to be modified with regard to risk taking, rewards, probabilities, misperceptions, and domestic and bureaucratic politics” (Lupovici 2010, 707).  Throughout history, deterrence theory has remained relevant, although it has needed significant revitalization throughout time in order to keep up with the times. The are various dependent variables that need to be addressed when researching deterrence theory.  In general deterrence theory, the following dependent variables are addressed “Status Quo, Defender Concedes, Conflict, or Challenger Defeated” (Quackenbush 2010, 69).  All of the above are the different options for this theory-defender concessions, all out war, the challenger is defeated, or if no dispute was initiated then it became the status quo. Because hostile action can be used at many different levels, it is important to clarify as a dependent variable what level they were at (all out war, a display of force, or a threat of force) (Quackenbush 2010, 70).  “Calculating the balance of deterrence to see whether it favors attackers or defenders was an art instead of a science even before nuclear weapons were invented. Now calculation of prewar balances and projection of their wartime capabilities isless important than estimation of the staying power of leaders and societies under unprecedented destruction” (Cimbala 1989,77).  An important dependent variable in the calculation is deciding what threat level you are going to counter the other actor with.  If the defender goes to far, they can push the attacker into an all out war, which is not the desired outcome of deterrence theory.  “The principal assumptions made by the [deterrence] theory include: (1) a message is relayed to a target group [e.g., it is wrong to murder, and if you take another’s life you could go to prison or receive the death penalty]; (2) the target group receives the message and perceives it as a threat; and (3) the group makes rational choices based on the information received” (Tomlinson 2016, 33).  Each scholar agrees with the main dependent variables, although they may name them slightly differently. The main independent variables of deterrence theory include “player types and credibility” (Quackenbush 2010, 70).  “Deterrence is not entirely unilateral. As theorists have pointed out, deterrence is a cooperative activity to a certain extent; if the opponent will not cooperate by deciding not to attack, then deterrence fails. The trouble with national leaderships strongly inclined to go to war is that they make very unpromising targets of deterrence threats. They are likely to ignore these threats or to strive to design around them” (Williams and Viotti 2012, 28).   For instance, if you continually tell illegal immigrants that they will be not allowed entrance to the United States, but you then give them government benefits, you are unable to use the deterrence theory to ensure they immigrate legally.  Conversely, if you tell illegal immigrants that they must immigrate legally and build a border wall to prohibit their illegal entry, you are ensuring that they are deterred from entering illegally.  General deterrence is the ‘‘deterrent effect of indirect experience with punishment and punishment avoidance and specific deterrence as the deterrent effect of direct experience with punishment and punishment avoidance’’ (Sitren 2012, 492). “Deterrence strategy relies on two basic conditions: the ability to retaliate after a surprise attack must be perceived as credible; and the will to retaliate must be perceived as a possibility, though not necessarily as a certainty” (Britannica 2017, 1). A classic example of immediate deterrence is the Cuban Missile Crisis (Quackenbush 2010, 61).  Although the United States was eventually successful, and “did get the Soviets to remove the offensive medium- and intermediate-range missiles from Cuba” how did  “Khrushchev came to estimate that he could get away with putting them there” (Cimbala 1989, 38)?  In this instance, the US failed at general deterrence theory, in that we did not make it known that we would not tolerate a threat.  This made it so Khruschchev felt he could get away with pretty much anything in regards to the US.  The US did not have credibility in his eyes.  “In other words, this was clearly a U.S. deterrence failure” and almost forced the “West to choose between capitulation or war in Europe. Given the obvious American superiority in nuclear-capable delivery vehicles of intercontinental range in October 1962, one must also wonder how Khrushchev was able to wait for so long before capitulating” (Cimbala 1989, 38). “Steps to ensure that deterrence is stable, such as by restricting first-strike capabilities unilaterally or by agreements” is extremely important to ensure the prevention of an all out war (Williams and Viotti 2012, 35). “States have always been able to seek deterrence through military strength” (Williams and Viotti 2012, 35).   A weakness of seeking deterrence through our military strength is that we have systematically built up our entire world stockpile of weapons.  “Imbedded in the logic of deterrence there is a dilemma: under conditions of mutual assured destruction, if both sides recognize it would be irrational to carry out their threats of nuclear retaliation, then no disincentive exists to keep either side from initiating an attack” (Sigal 1979, 569).  The theory of deterrence takes for granted that the other actor is rational, but what if the other actor was irrational (Sigal 1979, 569)?  Some enemies do not mind sending their fighters to die for the cause (terrorist actors) so will they really be rational when it comes to making these decisions? Another problem to be looked as is if deterrence theory is micro or macro-level.  Although the theory “boils down to individual decision making” more than macro decisions, both individual and macro level analysis is needed to understand the effects of deterrence theory (Tomlinson 2016, 37).  Can states implement both the macro and micro aspects of deterrence theory to dissuade terrorists and terrorist organizations (Lupovici 2010, 718)?  Some scholars argue that deterring terrorists will fail because the “defender’s capabilities (implementation of deterrence strategy) are limited”.  It is important to employ both threats to the terrorist individual and organization to succeed against terrorism (Lupovici 2010, 718). What does deterrence theory look like today? “Deterrence is the use of a threat (explicit or not) by one party in an attempt to convince another party not to upset the status quo” (Quackenbush 2010, 60).  One of the main requirements for deterrence theory to work is that the actor you are against is of rational thought and will be able to be deterred by use of a threat.  This can be a problem with some of the modern actors (terrorists are a common example).  Some people believe they are above the law, but are generally rational thinkers, can be a problem when employing deterrence theory.  “Even when a potential offender is rational and fears punishment, she will not be deterred if she is confident that the punishment will not follow her offense” (Lee 2017, 15). The “concept of deterrence by punishment…is defined as the persuasion of an opponent that the risk ? cost of an undesirable action it may take will exceed any possible gains” (Lupovici 2010, 707).  The “emerging fourth wave of deterrence theory” is about using deterrence on rogue states, terrorists, and in ethnic conflicts (Lupovici 2010, 719-721).  The only way to use deterrence theory today is with a two-pronged approach to the challenging actor or nation.  The attack must be used both on the macro and micro level, targeting both the individual attacker (or criminal) and the organization (or crime syndicate) that the individual is a part of.  There is still more research to be done on the effect of an individual (such as an illegal immigrant or lone-acting terrorist) being deterred by the actions of a nation.  Although deterrence theory is ever evolving, it is still very relevant today, as long as it is used in the proper manner.                                                                  BibliographyBritannica, The Editors of Encyclopaedia. “Deterrence.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., 12 June 2017, www.britannica.com/topic/deterrence-political-and-military-strategy.Cimbala, Stephen J. “3: Deterrence, Rationality, And War Planning.” In Strategic Impasse: Offense, Defense, and Deterrence Theory and Practice. Praeger, 1989. Https://psi-praeger-com.ezproxy2.apus.edu/topics/display/2048059?cid=138&sid=2041393.Lee, Hsin-Wen. 2017. “Taking Deterrence Seriously: The Wide-Scope Deterrence Theory of Punishment.” Criminal Justice Ethics 36 (1): 2–24. doi:10.1080/0731129X.2017.1298879.Lupovici, Amir. 2010. “The Emerging Fourth Wave of Deterrence Theory—Toward a New Research Agenda.” International Studies Quarterly 54 (3): 705–32. doi:10.1111/j.1468-2478.2010.00606.x.Punch, Keith F. 2016. Developing Effective Research Proposals. 3rd ed. Thousand Oaks, CA: Sage.Quackenbush, Stephen L. 2010. “General Deterrence and International Conflict: Testing Perfect Deterrence Theory.” International Interactions 36, no. 1 (Jan-March): 60-85.Sigal, Leon V. 1979. “The Logic of Deterrence in Theory and Practice.” International Organization 33 (4): 567–79. doi:10.1017/S0020818300032318.Sitren, Alicia H., and Brandon K. Applegate. 2012. “Testing Deterrence Theory with Offenders: The Empirical Validity of Stafford and Warr’s Model.” Deviant Behavior 33 (6): 492–506. doi:10.1080/01639625.2011.636685.Tomlinson, Kelli D. 2016. “An Examination of Deterrence Theory: Where Do We Stand?” Federal Probation 80 (3): 33–38. http://ezproxy.apus.edu/login?url=http://search.ebscohost.com/login.aspx?direct=true&authtype=ip&db=tsh&AN=121317709&site=ehost-live&scope=siteWilliams, Robert E., and Paul R. Viotti. “Chapter 3: Elements Of A General Theory Of Arms Control.” In Arms Control: History, Theory, and Policy. Praeger, 2012. https://psi-praeger-com.ezproxy2.apus/edu/topics/display/1995085?cid=138&sid=1994813