This is an answer I read on Quora forum by a Kashmiri called Mohan Dudha. I had known the ideological position on which Pakistan is formed and had also known Allama Iqbal's ex post-facto role as an ideologue of Pakiatsn. Dudha's answer is however provides the details. I only hope that he is both right and wrong -- right (in analysis) and wrong (in predictions). Read on:
Complex questions require long answers.
The core concept of the Pakistan Ideology is that Islam is the foundation of nationhood. In its purest form, this means that Muslims and non-Muslims can never share citizenship in a single nation because, for Muslims, their real citizenship is Islam and nothing else.
Iqbal wasin this: “Objection must, however, be raised when it is contended that in modern times nations are formed by lands and the Indian Muslims are advised to accept this view. Such advice brings before our minds the Western modern conception of nationalism, to one aspect of which it is absolutely essential for a Muslim to take exception. […] After getting the name of ummat-Muslimah from the Court of God, was there any room left for merging part of the form of our society into some Arabian, Iranian, Afghani, English, Egyptian or Indian nationality? There is only one millat confronting the Muslim community, that of the non-Muslims taken collectively.”
This is why none of the “Pakistani” heroes are actually Pakistani themselves. Muhammad bin Qasim, Tamerlane, Mahmud Ghaznavi, Babur, Muhammad Ghori, Salahuddin. None of them were Pakistani. However, because the core of the Pakistan Ideology is that Muslims form one nation, they are Pakistanis. I have myself had bizarre exchanges with Pakistanis on Quora. Cheemas, Chauhans and other Hindu lastnamed people who talk about themselves as though they are descended from these invaders and raiders. As an Indian, this is weird: They are basically Hindu by descent and their forefathers were the people who fought these enemies. But as a Pakistani, that is irrelevant. Conversion to Islam, for these people, severed their ancestral nationality. Mohammad Ghori killed Prithviraj Chauhan (after Chauhan defeated him and had let him go), and Khokhar Hindus killed Ghori in revenge soon thereafter. But Pakistani Chauhans and Khokhars idolise Ghori, not their own Khokhar and Chauhan ancestors. For an Indian, you cannot understand this because the worldview is just so different. You see them say something like “we ruled for 800 years,” which translates to something truly weird like “I have become the same people as the invaders who gained control over my ancestors, therefore I conquered my own ancestors.” It’s not going to compute for Indians. North Indians, especially, will see Zulfiqar Ali Bhutto, who is basically Bhatti (Rajput) and scratch their heads. The man’s actually a Hindu by descent. Again, won’t compute if you simply think that religion is a personal matter, but it will compute if you view it through Islamism (watered down in the case of Bhutto, but still there).
Indians and Pakistanis sometimes view each other and think they are similar countries, due to ethnolinguistic similarities. They are not at all. They are so different now as to be utterly foreign to one-another. Frankly, Iranians and Afghans have no chance of truly understanding this either, because this demands that they stop viewing themselves as legitimate nations as well. Pakistani ideologues were extremely specific in their demand that different Muslim countries should dissolve themselves into a single Muslim nation: “Butaan-e-rang-o-khoon ko todkar millat mein gum ho jaa, Naa Turaani rahe baaqi, na Irani na Afghani” (Smash the idols of race and lineage and dissolve yourself into the Islamic Nation, No Turanian should exist, No Iranian, No Afghan, Tulu-e-Islam, The Rise of Islam).
This is similar to what we would call Islamism today, which says Muslims are one nation and government in the Muslim nation should be run according to strict Muslim principles. Islamism is the core ISIS ideology as well (forget their barbarism for a second): Islam equals Nationhood. This is what inspired the driving out of the 25% Hindu and Sikh population of the territory that is Pakistan today to turn it into the 97% Muslim population it is today. This is the ideology of the Taliban also.
Jinnah flip-flopped between Islamism and Secularism, so you can easily find quotes from him supporting Islamism and Secularism. But the core of the Pakistan Ideology is that “Islam defines Nation” and this is why he said:
“Pakistan came into being the day when the first Hindu was converted to Islam” (March 1944, Aligarh). Iqbal specifically warned against any dilution of Islamism - “Jalal-e-badshahi ho ki jamhoori tamasha ho, Juda ho deen siyasat say to reh jatee hai changezi” (Whether kingly rule or democratic circus, removing religion from politics leaves mere anarchy). In Pakistan, this has created a great mobilisation to become more Islamic - whether discarding pre-Islamic, Hindu customs like Basant, or discouraging Punjabi and replacing it with the “more Islamic” Urdu, or scrubbing the language to replace the non-religious “Khuda Hafiz” with the more Islamic “Allah Hafiz.” Before 1971, this was also the source of a big disconnect between Bengalis and Pakistanis. Pakistanis simply could not understand why Bengalis wouldn’t simply abandon “the Hindu Bengali language” and adopt the more “Islamic Urdu.”
The problem, of course, is that Islamism (Islam meaningfully enshrined as National Self-Concept) is fundamentally incompatible with Democracy and Secularism. Pakistan’s slow slide into extremism was inevitable. The exact same thing will happen with ANY country that has a functional state religion, because it is a movement to actually bring the politics in alignment with the founding principle. This can only be arrested through sustained authoritarianism because, without it, a second state will inevitably emerge due to the widespread indoctrination of the people. Once this has set in, making a switch away from the National Ideology is close to impossible, unless something traumatic happens or some truly phenomenal leader appears and rules for an entire generation, or some other unprecedented externality (the Internet getting wired directly into human brains, causing everyone to be exposed to lots of diverse ideas constantly) occurs. Barring any of this, it seems likely that Pakistan will actually eventually have to accommodate the Talibani elements in the country politically. To simply fight them forever is not an option. In fact, evidence is that this has driven them into the arms of ISIS, with which they share political ideology (indeed, consider themselves to be citizens of the same Islamic nation).
So, it is likely that the future will see Pakistan becoming less secular, not more so. It is possible that some political brokering creates more secular and less secular sectors - socially, geographically or in some other way - in the country. This is essentially two states trying to avoid conflict by dividing a country between themselves. Indians should concede this reality. Educated Pakistanis are often in denial that any of this is happening, but it absolutely is. Simplistic, people-centered things like “Zia did xyz” or “India was lucky to have Nehru live on for a bit” are just so wrong. India was going to be a democracy no matter what. It is consistent with our civilisation and traditions. I should also note that there is absolutely nothing that says that Muslims have to believe the Pakistan Ideology or Islamism. It’s just an ideology. If you don’t think that way, you won’t be an adherent of it. The vast majority of Indian Muslims think it is rubbish. Some British Muslims, however, do not ().