Handing Afghanistan a Peshawar could solve a lot of problems. Handling Peshawar is too much for Pakistan now. Pakistan could use break from terrorism by handing the Peshawar to Afghanistan might solve terrorism problem. I know this might sound provocative and unlikely precedent.
Pretty sure, Kashmir will belong to Pakistan; bigger portion for Pakistan as according to Ghzwa-e-Hind. Meanwhile, try non-violence method by giving Pukhtoonkhwa to Afghanistan and that will be Afghanistan's problem. Therefore, that shouldn't stop Pakistan from having border controlled to reduce terrorism for starter.
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Nuri Natt
Pakistani government during that time actually pushed them to Bangladesh after isolating them for so long. If the government hasn't isolated them, maintained friendly relationship with East Pakistan, there would never be question of Bangladesh.
Even today, Pakistan still enjoys the support from Bangladesh. I am afraid we cannot say the same for Afghanistan, or Afghan immigrations in Pakistan for that matter.