Threat is used by the stronger to force the weaker to do things in the interest of the stronger (seeking revenge at the same un-ethical level, the weaker may only have recourse to manipulation) At the social level, threats of punishment function in combination with promises of rewards, as a global argument from threat and promises of reward.
1. Ad baculum : argument from threat
Threat speech, or argument from threat, or appeal to fear, (Lat. ad metum; metum, “fear”) has also been called:
— By metonymy, the “argument from the stick” (Lat. ad baculum; baculum, “stick”), or “from prison” (Lat. ad carcerem; carcer, “prison”), or “to the purse” (ad crumenam; crumena, “purse”; by a double metonymy).
— By metaphor, the “thunderbolt argument” (Lat. ad fulmen, fulmen, “lightning; violence”).
The prospect of a more or less imminent danger scares the person off the next planned action and induces new, more or less specific kinds of behavior. The threatened person feels an emotion, ranging from apprehension to fear or panic. The feeling depends on the mode of production and treatment of the source, which may or not be well defined (“we feel that something will happen to us”), and enter into a controllable causality (“we are living in a clash of civilizations”). If the threat is causal, generalized and uncontrollable (“the world is falling apart”) threat discourse will result in anxiety, fear, anguish, and even mass panic.
Two kinds of threat can be identified on the basis of whether or not the source of the danger is an intentional agent:
— The source is intentional, “threatening enemies assail our civilization”.
— The source is non-intentional, the danger comes from the material world, and is interpreted as causal: “the storm threatens the crops”; “you are at risk of cancer”.
The non-intentional source can be human. The “shapes passing by in the fog” for example can be perceived as threatening despite the fact that they are actually employees returning home from the office. This is the difference between N0 terrorizes N1 and Na terrifies Nb. The subject of terrorizes is intentional, N0 wants to frighten N1 (the gang is terrorizing the honest citizens), while the subject of terrifies is not necessarily intentional, and not necessarily human.
Fear speech expresses, inspires and strengthens a feeling of danger and insecurity, through oriented narratives and arguments which bring together the reasons, valid or not, to be afraid. Fear strategies can take two distinct orientations. They can either leave their targets plagued by anxieties, or can propose solutions to control or suppress the danger, S. Pathos; Emotion.
Fear speech can be based upon a real threat (climate change), or an invented one (alien invasion). In both case, the agent can be intentional (terrorists) or non intentional purely causal (climate change). It may or may not be correlated with hate speech.
In the hands of the established power, threat and fear, like joy and reward, can be used as powerful instruments of social cohesion and social control in societies which abide by the doctrine, “let the good rejoice and the wicked tremble”.
Threat speech is no different from fear speech, where the speaker refers to an external threat. Threat speech may also be conveyed by an individual A expressing his or her intention to cause damage or harm to another individual N, if N does not comply with such and such requirement as imposed by A. In this case, the same person occupies the roles of speaker and villain. Such threat speech has an “either… or…” format:
Either you do this for me — which is, I agree, quite unpleasant for you — or I do that to you — which is really much more unpleasant for you.
Whether this second kind of threat speech should be considered an argument or not is disputable. If we are accosted on a street corner and presented with the option of keeping our money or our life, we are likely to make a rational choice, opting to keep our life. When asked to explain where our money has gone, the existence of such a threat will be considered to be a good reason and a fully satisfactory justification for the loss of the money.
At the political level, balanced threats are the basis of nuclear deterrence; and it would be quite irrational not to take into account the fears imposed on the populations affected.
2. Threat and argumentation by the consequences
Threats can be efficiently presented as an argument by the consequences, where causality is veiled under agentivity. Rather than openly taking on the role of a villain, the speaker poses as the unwitting agent of a negative event provoked by the irresponsible behavior of the future victim. The blackmailer presents himself or herself as an advisor, and frames the interlocutor as the one responsible of future misfortune:
Question: Should the company grant a salary increase to its employees?
Labor’s representative: — If there is no increase, we’ll occupy the plant!
Employer’s representative: — If you persist in your unrealistic demands, we’ll be forced to close down the plant and cut back jobs.
The same change of footing is operated by the politician presenting his or her own political decision as motivated by “the order of things”, S. Weight of Circumstances.
3. Arguments from threat and promise
The Chinese philosopher Han-Fei proposes a theory of power as an expert blending of the two measures (Han-Fei, Tao); that is the two basic material interests motivating human actions, punishments and rewards, excluding the rationality issue, or other kinds of value, such as justice.
This kind of management of human actions exploits two antagonistic psychic movements, fear and suffering of punishment, desire and joy resulting from reward. If arguing is making somebody do something, or dissuading somebody from doing something, threat and promise would thus be the two argumentative speech acts par excellence — S. Authority; Pragmatic Argument.
The everyday expression “the carrot and the stick” rightly associates the appeal to financial interest, with the traditional ad baculum argument; which might more fittingly be called ad baculum carotamque argument. The latter is no more “rational” than the former, although it is certainly considered to be more acceptable by many.
Appealing to money is not the only way to get what one wants; rewards and punishments might draw on everything and anything that humans may desire. This might include, in particular, power, pleasure, and money, S. Values.
The ad crumenam argument (Lat. crumena, “purse”), is mentioned in Tristram Shandy, where it refers to the introduction of considerations about money in a debate:
Then, added my father, making use of the argument Ad Crumenam, — I will lay twenty guineas to a single crown piece, […] that this same Stevinus was some engineer or other,—- or has wrote something or other, either directly or indirectly, upon the science of fortification”
Laurence Sterne, The Life and Opinions of Tristram Shandy, gentleman, 
4. Appeal to superstition
Lat. ad superstitionem, superstitio, “superstition”
The label appeal to superstition was introduced by Bentham, to refer to the fallacy of “irrevocable commitment”, which prohibits the revision of prevailing political dispositions (, p. 402); S. Political Arguments.
— “Fallacy of vows or promissory oaths; ad superstitionem”: “But we swore!”
— “Fallacy of irrevocable laws”: “But that wouldn’t respect the constitution!”
Superstition is invoked here because of the oath supposedly taken to honor the will of a sacred Supernatural Power, or of the Founding Fathers, “who knew better”, and “to whom we owe everything”. Failing this duty would constitute not only a lack of respect for the authority of the Founding Fathers, but a religious or moral sin provoking some supernatural revenge. It can be assumed that such threats are the flipside to promises that submission to the Law will be duly rewarded. As a consequence, the appeal to superstition as defined here is a subspecies of appeal to threats and promises, made by transcendental powers. In this case, the argument represents a somewhat materialistic version of the argument from faith.
Non-cynical, ordinary citizens consider that politicians must honor their election commitments. It would be difficult for failed politicians to invoke the fallacy of irrevocable commitment to perpetually justify their alliance and agenda reversals.
 In The Complete Work of Laurence Sterne. Delphi Classics, 2013, p. 98.