The assignment does not specify a particular context in which the topic of deterrence is being discussed. That is fine, as a basic definition is not contextually required. “Deterrence,” in its simplest understanding, means dissuading another individual or group of individuals from carrying out a specific act because the reprisal would be so severe that the initial hostile act would not be worth the cost. “Deterrence” as a concept, however, usually occurs within one of two contexts: nuclear deterrence (or deterrence of any other level of military conflict) or crime and punishment.
In the context of nuclear deterrence—or deterring another party (e.g., the other government/society) from carrying out a hostile act, such as invading or using weapons of mass destruction (nuclear, chemical, biological)—deterrence refers to the attempts to communicate to the other party that the consequences the initial act would provoke retaliatory measures that would cause extremely high level of death and destruction. During the Cold War, a nuclear conflict was avoided because each side, the United States and the Soviet Union, calculated that any use of nuclear weapons would inevitably result in the destruction of their own country.
Here is where the concept of a rational actor comes into play: deterrence was assured so long as each side was governed by rational leaders who could be counted upon to make thoughtful, informed decisions based upon a realistic perception of the situation.
In the context of crime and punishment, deterrence refers to the notion that the risk of imprisonment or worse (i.e., capital punishment) would cause potential or actual criminals to refrain from carrying out certain acts out of fear of the consequences. They are, in effect, deterred from acting illegally out of concern for a particularly severe form of punishment, such as a long prison sentence or the death penalty.
In both contexts, the success of deterrence is dependent upon the ability of the party to be deterred to think and act rationally. The party to be deterred must be capable of rational thought regarding consequences. This where deterrence theory acknowledges that deterrence may fail. In the international context, not all leaders are considered “rational” from a conventional perspective.
In other words, leaders of the United States and the Soviet Union could presumably expect that the other side was acting rationally (though post–Cold War revelations have revealed that such was not always the case, especially during the early 1980s). The concern in the United States regarding then-Iraqi leader Saddam Hussein was that he was not a rational actor and would strike out with weapons of mass destruction (which, it turned out, did not exist in any meaningful sense) without concern for the consequences. Similarly, many leaders around the world, especially in Asia, are concerned that North Korean leader Kim Jong-un is irrational, unpredictable, and capable of using the nuclear weapons his country has succeeded in building.
The calculus within the context of criminal justice is even more complicated. Many criminals—although by no means all criminals—exhibit some sign of mental impairment that influences their thought processes. Members of organized crime such as the Mafia are known for their tendency to calculate risk, both with respect to concerns about the criminal justice system and about other organizations against whom they may be maneuvering. However, many individual criminals, especially those with identified mental illnesses, lack the mental capacity to make rational decisions; they simply act out of impulse, sometimes influenced by addiction.
These are the individual for whom deterrence is often ineffective. Thoughts of consequences may not enter into their calculations. Then, there are those criminally oriented who are rational actors but who choose to commit crimes anyway out of necessity (e.g., fear of retribution from fellow gang members) or simple need (shoplifting to feed oneself absent financial resources).
In short, “rational actor” is a concept that can be difficult to apply in discussions of deterrence. One person’s definition of “rational” is not necessarily shared by others. Fear of consequences may not deter depending upon the factors motivating the criminally inclined. Inability to calculate risk and to envision consequences the severity of which make the initial act irrational is a common variable when discussing deterrence.