A strong, independent Afghanistan is perceived as an existential threat to Pakistan
Just why is Pakistan interested in installing a friendly regime in Afghanistan? If you read books and articles written over the last couple of decades, you will come across arguments such as the need for “strategic depth” to counter India, to prevent a pro-India regime in Kabul that will result in the Indian encircling of Pakistan and, even more grandly, to create an Islamic centre of power that stretches from the shores of the Arabian Sea to the Caucasus mountains. Going by the statements of members of the Pakistani establishment and some of its commentators, these are indeed the reasons why Pakistan wants to dominate Afghanistan.
Yet, to a large extent, the ambition and the paranoia that motivates these goals are in the realm of fantasy. Important people might believe in these fantasies, which means they must be taken seriously, because those important people do act on the basis of their delusions. However, there is also an argument to be made that these fantasies, paranoias and strategic sophistries are used to mask the real motive.
Pakistan’s real motive in seeking to dominate Afghanistan is the fear of its own dismemberment. Until the Soviet invasion of Afghanistan in 1979, Islamabad’s main agenda was to prevent Kabul-supported Pashtun and Baloch nationalism from escalating into full-blown movements for independence. The strength of Pashtun nationalism and Kabul’s rejection of the Durand Line (which continues to this day) create deep insecurities in Islamabad, causing it both to bolster Islamism as an ideological counter, sponsor political instability in Afghanistan and attempt to install a friendly regime there.
It is a matter of historical fact that Pakistan—under President Zulfikar Ali Bhutto—began training Islamist militants in 1973, long before the Soviet invasion. Burhanuddin Rabbani, Gulbuddin Hekmatyar and Ahmed Shah Massoud received training in Pakistani camps so that Bhutto could counter Kabul ‘forward policy’ towards Pakistan. Kabul’s policies over the Durand Line had caused Pakistan to close its borders with Afghanistan in 1961. When the Baloch insurgency erupted in the early 1970s, Kabul (under the Daoud regime) supported it. Bhutto’s response was to nurture proxies in the form of Islamist militants—an old trick for the Pakistani establishment—under the leadership of the then Brigadier Naseerullah Babar, who as Inspector-General of the Frontier Corps, set up training camps in North and South Waziristan. More than 5000 militants were thus trained between 1973-1977. Again, it must be stressed, before the Soviets invaded. The narrative that most people accept—that Pakistan’s sponsorship of the mujahideen was a response to Soviet invasion of Afghanistan—is factually incorrect. [Rizwan Hussain’s Pakistan and the Emergence of Islamic Militancy in Afghanistan has a good account of this]
The Pakistani establishment fears that a strong independent Afghanistan—like the one that existed up to the mid-1970s—will pursue an irredentist agenda, claiming the Pashtun areas of Pakistan. People in the tribal regions of Pakistan have only a tenuous association with the Pakistani state, and even for people in the so-called ‘settled areas’ of Khyber-Pakhtunkhwa, age-old Pashtun solidarity is often stronger than allegiance to a geopolitical entity called Pakistan. Afghanistan can well decide to support the insurgency in Balochistan to weaken Pakistan enough. Therefore, Pakistani strategists can see an existential threat in a strong, independent Afghanistan.
They can’t, however, state this as the official reason, because to do so would be admit the hollowness of the idea of Pakistan. That’s why fantastic notions of strategic depth, pre-empting strategic encirclement or building a Central Asian caliphate come in useful. “Strategic depth” is a plausible justification to convince patriotic Pakistanis of why their military is interfering in Afghanistan. Islamabad’s case appears a lot more ‘understandable’ to international opinion if it cites the fear of Indian encirclement rather than fear of Pashtun and Baloch self-determination as the reasons for its actions. Domestic and foreign Islamists will be enthused by the idea of flying the green flag of Islam all the way to the borders of Russia.
Theoretically, Pakistan’s military-jihadi complex might be persuaded to stop destabilising Afghanistan if it were convinced that Kabul will not lay claim to Pashtun lands east of the Durand Line. In practice that would be nearly impossible, not least because Afghan nationalism will not accept it. Even Mullah Omar’s Taliban regime didn’t.
Some matters will be decided by the force of arms. If at all.