Thats true whenever military tried to enter into political system ,national security got compromised. And we have seen it in 1971.
Once Pakistan was created, Jinnah reportedly tried to open the membership of Muslim League(ML) to all citizens of Pakistan (irrespective of religion), or alternatively dissolve it (as it had achieved its goal) .. Unfortunately he was unsuccessful ... Jinnah, who had been a Bombayite, had no similar roots in Karachi (the new Capital) .. Time and again he was made aware that he was an outsider. Similarly, many of his close associates (like Liaquat Ali Khan, Ibrahim Ismail Chundrigar etc. ) had no roots in Pakistan ... This was one of the reasons the ML didn't want to hold general elections in Pakistan... The first General Elections were held in Pakistan in 1970 (i.e. 23 years after the creation of Pakistan), whereas, In India, the first General Elections were held in 1951-52 ..
After the death of Jinnah in 1948, there was not a single person in ML who could effectively replace Jinnah as the undisputed leader of the ML or Pakistan. This was when "Islam" was brought into politics by the Leaguers for the first time (to be used as a political tool) .. "Prostitution of Islam for political ends" as Iskander Mirza described it later !!
One very important (but often ignored) development was the 1954 provincial elections held in East Pakistan .. Elections were due in 1951, but the ML used delay tactics (though it didn't help them in the long run). The elections resulted in a landslide victory for the socialists and nationalists i.e. United Front which won 228 seats in a House of 309 (including nine reserved seats for women). On the other hand, the Muslim League, the party in power directly or indirectly ever since 1937, managed to get only 7 seats ... This heralded the rise of Bengali Nationalists .. But On May 30, just after two months, the ministry was dismissed and direct governor’s rule was imposed.... Now ML knew that in case general elections were held, the Bengali Nationalists would come to power in the center as well (as Bengalis formed the "Majority"), and the political hegemony of ML would be over ...
This was when ML decided to use "Islam" as a political tool against the socialists of East Pakistan ... And those Mullahs who had openly opposed Jinnah and proudly rejected Jinnah's "unIslamic" ideals, were invited to join ML (see Munir Report of 1954 for details) ....... The country was named "Islamic Republic" in 1956 ... We were the first one in the world to add prefix "Islamic" to our republican status .. ... Elections were further delayed by ML .. In 1957 most of the detractors came together in the left-wing and secular National Awami Party (NAP) and were confident that the party was in a good position to win the most seats in the promised direct elections (that were to be held in 1958). But then first Martial Law was imposed in the country in late 1958 by the "elected" president of ML who invited Army to take over hoping that this would keep Bengalis (and others) permanently away from the corridors of power, as they had almost no representation in the predominantly Punjabi Army of Pakistan ... (But this proved to be "catastrophic" in the long run ... No amount of "Islam" or "military force" could hold Nationalist Bengalis for long ... And in 1971, we paid the price of "selfish" policies adopted by the ML) ..
It was the Muslim League power hungry politicians who didn't give democracy a proper chance to grow and prosper in the newly born state of Pakistan. Army came in much later (invited by Muslim Leaguers).
It's always easy (in fact fashionable) to bash Pak Army and hold it responsible for all our ills ... Politicians are equally (if not more) responsible ...
https://defence.pk/pdf/threads/the-system-by-wajsal.455694/page-8#post-8823598