Afghanistan has long been a challenge for Pakistan, with a history of animosity between the two nations.
Despite the occupation by the Soviets and Americans, Pakistan has maintained a decent relationship, but the hostility persists, particularly under the Taliban.
The history of Afghan animus is well established.
Pakistan has often taken a conciliatory approach, but there is a growing sentiment that it's time to respond in a way that Afghanistan will understand.
Nations have historically defined their territories and established defensible borders, such as Czarist Russia and Iran.
Author's summary: Pakistan faces ongoing challenges with Afghanistan.