Afghan war was a gift of your favorite Bhutto, whose ISI chief in the early 70's the infamous Gen. Naseerullah Babur AKA butcher of Karachi recruited the budding Islamist student leaders Ahmed Shah Masood and Gulbadeen Hikmatyar, they were a twinkle in Bhutto's eyes long before Zia came on the scene. And after that meddling and a series of few more debacles culminated in the red Army's motorized rifle units coming eyeball to eyeball with the Frontier Constablory across the Durrand line, Pakistan had little choice but to resist.All out gift of the Afghan war. (1979-1990) And once US left in 1990 result can be seen in economic numbers. Again during the Musharraf era, the Second Afghan war...check the economic indicators. And after Musharraf ... massive crisis loomed and the list is very long.
US prefers to deal with a dictator or a single window. Democracy is doesn't fit in US regional or international interests.
Unlike his lesser predecessors who gave India a pass on Kashmir when it was handed to them on a platter by the Chinese and surrendered the eastern wing without firing a shot or his successors who rolled over in prostration after one phone call, Zia showed enormous courage to stand up to a super power.
And the fact that it also provided a cover to continue the development of nuclear weapons was also a bonus.