From Strategic Depth to Strategic Liability: The Collapse of Islamabad–Kabul Ties

When Kabul fell in August 2021, Western capitals watched with dread. Islamabad barely hid its satisfaction. American transport planes lifted off from Hamid Karzai International Airport, closing twenty grinding years of occupation, and inside Pakistan’s deep state the mood was one of historic vindication. For decades the country’s security thinking had rested on “strategic depth”: a friendly, pliant government in Kabul that would shut India out of the western flank and quiet a porous border. Then came the photograph, of senior Pakistani intelligence officials sipping tea in the lobby of Kabul’s Serena Hotel days after the takeover. It said what everyone assumed: the new rulers would remember their benefactors.

They did not. History is hard on short-sighted victories, and the euphoria soured fast. Pakistan’s original error was misreading the Taliban’s motives. Islamabad had treated them as one obedient proxy, brushing aside Pashtun nationalism and the binding force of global jihad. Once settled in the presidential palace, the Taliban stopped behaving like an asset and started behaving like a state, with survival instincts and ideological commitments of its own. The honeymoon barely lasted; an idealised alliance became an existential security problem.

The sharpest crack was the Tehreek-e-Taliban Pakistan (TTP) and its sanctuary on Afghan soil. For years Islamabad had comforted itself with a story that terrorism at home was fueled by hostile foreign intelligence agencies working under the Western-backed government in Kabul. Expel those agencies, and the Afghan Taliban would surely dismantle the TTP and hand over its leaders. Wrong. Kabul saw the TTP not as a bargaining chip but as ideological brothers-in-arms who had fought the Americans in the same trenches.

Instead of a crackdown, Kabul nudged Islamabad toward peace talks with the militants, and the talks backfired badly. Hundreds of heavily armed TTP fighters slipped back into Pakistan’s border regions under cover of a ceasefire, then regrouped, rearmed and unleashed a bloody campaign against security forces and civilians alike. Former Prime Minister Anwaar-ul-Haq Kakar caught the mood in Islamabad when he said no sovereign nation could tolerate a neighbour harbouring the killers of its citizens, and that Pakistan’s patience was exhausted.

The border itself soon became hostile. Pakistan had sunk immense money, manpower and years into a chain-link fence along the 2,640-kilometre Durand Line, meant to regulate movement and stem militancy. The Taliban, like every Kabul regime before them, rejected the British-era boundary outright. Their fighters pulled down sections of the fence, filmed it for social media, and fought deadly skirmishes with Pakistani border guards. The illusion of a compliant neighbour shattered; what Pakistan now faced was an emboldened, conventional force that refused to recognise its sovereignty.

By late 2023 quiet diplomacy gave way to coercion. Appeals to Islamic solidarity were going nowhere, so Pakistan reached for its economic and demographic leverage. It announced the expulsion of over 1.7 million undocumented Afghan refugees, many of whom had lived in the country for generations—a sweeping, controversial move meant to tell Kabul that shielding the TTP would carry a heavy human and economic cost. Stringent visa rules followed, along with repeated closures of the Torkham and Chaman crossings, the main arteries for commerce.

The fragile, sanction-hit Afghan economy took a beating, but the first casualties were traders on both sides of the frontier. For centuries the borderlands had worked as one interdependent economy; politically driven closures turned busy hubs into economic graveyards. Trucks loaded with perishables—fruit from Kandahar, pharmaceutical and agricultural supplies from Peshawar—sat rotting in multi-mile queues under a scorching sun. Small traders, customs clearers and daily-wage labourers lost their livelihoods overnight. In Chaman, where families straddle the arbitrary line, strict passport and visa rules wrecked the informal “allowance” system that had sustained the region for generations. The Taliban did not capitulate. Border populations were alienated, a smuggling black market flourished, and Kabul drifted deeper into the economic orbits of Beijing and Tehran.

Beijing, watching with anxiety, has become a reluctant mediator caught between two volatile partners. Its priority is the multi-billion-dollar China–Pakistan Economic Corridor (CPEC), a flagship of the Belt and Road Initiative that militants, some using cross-border sanctuaries, have repeatedly attacked. A full breakdown in Pak-Afghan relations would unsettle the regional security order and endanger Chinese personnel, so China has quietly used its diplomatic and economic weight to broker trilateral talks. The aim is an uneasy coexistence: Kabul committed against regional militancy, Islamabad stable, and Chinese infrastructure reaching a desperate Afghanistan without Pakistani investments going up in flames.

Underneath, nothing changed. The flashpoint came in the early hours of March 16, 2024, when a coordinated, sophisticated suicide assault hit a Pakistani military outpost in Mir Ali, in volatile North Waziristan. Seven soldiers died, two of them senior officers. For Islamabad it was a red line crossed—no longer a local border skirmish but a direct provocation by militants operating with impunity from Afghan havens. President Asif Ali Zardari warned that Pakistan would not tolerate cross-border terrorism and reserved the right to defend its citizens and borders by any means necessary if Kabul failed to act.

Forty-eight hours later, on March 18, Pakistan struck back with airstrikes deep inside Afghanistan, targeting suspected TTP sanctuaries in Khost and Paktika. Never before had Pakistan openly used its air force inside sovereign Afghan territory—against an administration it had helped bring to power.

The Taliban’s answer was swift and uncompromising. Chief spokesman Zabihullah Mujahid said the Islamic Emirate does not allow anyone to use its territory against others, but insisted Pakistan should not blame its own security failures on Afghanistan, and warned of dire consequences it could not control. Heavy artillery fire then crossed the border onto Pakistani military installations. The last veil of brotherhood was gone, exposing a raw, militarised conflict between two heavily armed states.

Today the relationship is frozen in a dangerous stalemate. Strategic depth is dead, buried under cross-border airstrikes and shattered trust. Pakistan now sees Afghanistan not as a partner or a buffer but as a primary source of instability and an active threat. The channels still open are cold and transactional. Kabul nurses grievances over the refugee expulsions and economic blockades, and sees an overbearing neighbour; Islamabad insists normal relations are impossible while Pakistani blood is shed by terrorists operating from Afghan sanctuaries. From a celebrated takeover to the brink of conventional war: a grim lesson in geopolitical hubris, leaving two nations trapped in mutual distrust along one of the world’s most volatile frontiers.