Popularized by former US President Richard Nixon, but originally described by Niccolò Machiavelli back in the early 1500s, the “Madman Theory” of negotiation and politics says, in essence, that sometimes it can be beneficial for your opponents to think you’re insane or otherwise unstable.
The prime, theorized benefit of being thought volatile in this manner is that your enemies (or those on the other side of some kind of negotiation) will go out of their way to avoid provoking you, because their expectations of what a normal, non-insane person would do when thus provoked might lead to outsized, even horrific and deadly consequences.
In Nixon’s case, this meant that by acting like he was irrational and prone to belligerent overreaction, he was sometimes able to keep Soviet leaders from overstepping, worried that if they took too many liberties or assumed too much they might trigger a nuclear war (and thus, wipe out most of humanity and render the planet uninhabitable) because they caused the US President to go ballistic.
Machiavelli’s contention was somewhat different, derived as it was from a historical assessment of the Roman Empire.
His observation about how best to deal with tyrannical rulers was that you must either distance yourself from them, or bind yourself to them to the point that you’re praising and aiding them in efforts that are oppositional to your own beliefs and ends—behaving in a manner that other people might consider to be crazy, because in doing so you’re able to get closer to a loci of power (he was describing Brutus’ behavior, so in that specific case, “playing crazy” ultimately made Brutus so trusted that he was in the position to assassinate the most powerful person in the empire).
Both flavors of Madman Theory have been criticized for being generally ineffective, most of the time, in part because this approach can be misconstrued as raw, purposeless aggression, and because the supposed madman may be seen as so beyond reason that it’s more logical to take them out (or otherwise render them harmless) than to attempt to understand or deal with them.
It’s also been posited that this stance can lose its effectiveness over time, especially if the person playing mad never adopts another stance, which implicitly reduces the incentive of those on the other side of negotiations to give in to their demands (as either way the madman will remain mad, and thus, unreasonable and perhaps dangerous).
The alternative to this always-on stance (which US President Trump has been accused of striking) is something closer to Nixon’s approach, which was meant to imply that he was crazy because he’d been pushed too far; so if the other side did something to placate him, he might return to a stance of sanity and predictability.
All of this, whichever version of it we might be discussing, falls under the larger header of “deterrence,” and in some cases an approach to negotiation called “brinksmanship”—the former of which is meant to keep someone from doing something you don’t want them to do, and the latter of which involves pushing things to the brink: playing chicken with your opponent and hoping they back down before you do.
Playing the role of a madman under such circumstances can sometimes force the other person to balk, as long as they believe you truly won’t back down, no matter how significant the consequences of not doing so.
But if they’re playing a similar game, if they don’t believe you’re as crazy as you’re pretending, or if they don’t understand whatever it is you’re trying to communicate by striking this stance, this sort of gambit can lead to far worse consequences than even the most brutal of failed negotiations.