Tactical nuclear warheads are more serviceable for use in intimidation and retaliation toward enemies, as they are considerably less catastrophically destructive than those of current nuclear arsenals.  For deterrence to function, rogue states and other international actors with nuclear capabilities, such as North Korea, must believe that their would-be target will retaliate in kind if attacked, tactical nuclear weapons provide a middle option. Given that these rogue states would likely only have access to low-yield nuclear weapons, it is unlikely that they would be able to launch a nuclear attack capable of more than damaging a Western city. Furthermore, the relative difficulty of developing deliverable nuclear weapons means that rogue nations are increasingly looking toward the acquisition and development of alternative weapons of mass destruction, such as chemical, biological, and radiological weapons. Were the United States, or another nuclear power, to be attacked by any of these weapons, it is unlikely that it, or the international community would consider the deployment of a strategic nuclear strike in retaliation to be justified. The response would certainly be disproportionately large, as strategic nuclear missiles can easily level cities, even with the smallest possible payload. This means that in order to maintain effective deterrence, nuclear powers must shift from the paradigm laid out by the doctrine of Mutually Assured Destruction to a "flexible response" doctrine, in which countries deploy arsenals of much smaller, tactical nuclear weapons that their enemies honestly believe they will use if provoked. By equipping themselves with a range of weapons, so as to be able to scale responses appropriately, nuclear-armed countries are far likelier to deter potential aggressors in future 1. Pakistan's military serves as an example of such tactical nuclear capability ready for action; its army is armed with an arsenal of mini-nukes that can be used to destroy whole tank formations, with little radioactive fallout dispersing beyond the battlefield. These weapons serve to redress the balance between Pakistani and Indian conventional military capacity. As Pakistan is woefully outnumbered and outgunned in conventional weapons, its tactical nuclear arsenal can deliver devastating damage to massed Indian army formations, preventing any potential invasion2. Clearly, tactical nuclear weapons are useful weapons in a country arsenal, preparing it to be more flexible in its application of nuclear force. 1 Reynolds, Paul. 2003. "Mini-Nukes on US Agenda". BBC News. 2 The Economist. 2011. "A Rivalry that Threatens the World". The Economist.