What critical vulnerability is associated with the Mutually Assured Destruction (MAD) doctrine?

The critical vulnerability associated with the Mutually Assured Destruction (MAD) doctrine is its reliance on the rationality of decision-makers on both sides. MAD assumes that no leader would initiate a nuclear attack because the inevitable retaliation would result in the destruction of their own society. However, this premise breaks down if one or both sides are led by individuals who are irrational, miscalculate the risks, or are willing to accept catastrophic losses for ideological or other reasons. Another significant vulnerability is the potential for accidental war. False alarms, technical malfunctions in early warning systems, or misinterpretations of an adversary's actions could lead to an unintended nuclear exchange. The doctrine also struggles to address the possibility of limited nuclear strikes or the use of tactical nuclear weapons. A limited strike might be perceived as a 'test of resolve,' potentially escalating the conflict in unpredictable ways. Furthermore, the rise of non-state actors with access to nuclear weapons or the ability to conduct a 'dirty bomb' attack poses a challenge to MAD, as deterrence may not be effective against such actors. Finally, the development of effective missile defense systems, while intended to enhance security, could undermine MAD by reducing the credibility of the retaliatory threat, potentially tempting a first strike.