The doctrine is divided into four different thresholds before nuclear weapons would be operationally activated during a conventional or nuclear war with an aggressor state. In the event of war, for instance between India and Pakistan, the
Indian Armed Forces' numerical superiority and large stock of conventional weaponry is most likely to overwhelm Pakistan. Therefore, in a deteriorating situation, where an Indian military aggression is more likely to penetrate through Pakistan's defenses (or has already breached the main defense line causing a major setback to overall defense) which cannot be reversed by conventional means, the government would be left with no other option except to use nuclear weapons to stabilize the situation, with a
first strike. The rationale behind the doctrine is to prevent Pakistan from any military intervention (both conventional and surgical) that would lead to the disintegration of the country, as it did in 1971 (see
Indo-Pakistani war of 1971). South Asian affairs expert, Professor
Stephen P. Cohen calls the strategy of Pakistan an "option-enhancing policy". According to the
International Institute for Strategic Studies (IISS), the definition of the four potential thresholds has been refined from the first thresholds which were mentioned by officials at the Pakistan
National Command Authority (NCA) in late 2001. • Spatial threshold - The military penetration of Indian Armed Forces into Pakistan on a large scale may elicit a nuclearized massive retaliation, if and only if the
Pakistan Army is unable to stop such intervention. For instance, many analysts, including some Indians, believe that the
Indus Valley— the "
lifeline" of Pakistan— is one of many other "red lines" that Indian forces should not cross. The capture of key objectives in this crucial northeast–southwest axis might well provoke nuclear retaliation by Pakistan. • Military threshold - The complete knockout or comprehensive destruction of a large part of the
Pakistan Armed Forces, particularly and most importantly the
Pakistan Air Force (PAF), could lead to a quick nuclear response if Islamabad believed that it was losing the cohesiveness of its defence and feared imminent defeat. A senior ranking PAF officer maintained that "orders given to PAF (and its
missile command) are identical to the guidelines given to the
NATO commanders during the
Cold war crises". This criterion is even more important for the Pakistan Armed Forces because of its critical role in maintaining the country's stability. As noted above, an attack on a nuclear installation has also been posited as a threshold. According to the PAF, this threshold would also be breached by the use of chemical or biological weapons against Pakistan, and would provoke a massive retaliation. • Economic threshold - This level implicitly and explicitly refers for the countermeasure operations of the
Pakistan Navy. Economic strangulation and economic blockade are also potential threats to Pakistan, if the Navy is unable to counter them effectively (for example, see operations:
Trident and
Python in 1971). This primarily refers to a potential
Indian Navy blockade of
Sindh and coastal cities of
Balochistan, or the stoppage or significant reduction of Pakistan's share of water from the
Indus,
Jhelum and
Chenab Rivers under the 1960
Indus Waters Treaty. It could also refer to the capture of vital arteries such as the Indus. • Political threshold - Finally, Pakistan's geostrategists, game theorists, political strategists and planners suggest that a destabilization of the country by India could also be a nuclear threshold if Islamabad has credible reasons to believe that the integrity of the country were at stake. Stated scenarios are political destabilization or large-scale internal destabilization which the
Pakistan Marines (along with the
Civil Armed Forces) are unable to stabilize effectively. One example would be encouraging the breakaway of one or more of Pakistan's provinces (as in during the
Bangladesh Liberation War). • == See also ==