When we look at the political causes, we can see that there are three main ones. The first is that Pakistan comes into existence as a constitutional federation of different provinces. The constitution making process is to produce a final constitution for the country. Unfortunately, this process gets delayed and then gets disrupted owing to the fear in the ruling circles of the western wing of the country that a democratic system will lead to a permanent majority of the eastern wing because that is where the majority of Pakistanis happen to live at the time of independence. So, Pakistan’s military and bureaucratic leadership intervene in the political process and as a result of these interventions, they introduce various steps that undermine the democratic majority of the East Pakistanis. These steps include the creation of the One Unit in West Pakistan, the imposition of artificial parity of representation between the two wings and the intervention in politics in order to remove Prime Ministers from the Eastern Wing, like Khawaja Nazimuddin, Mohammad Ali Bogra and Hussain Suhrawardy, who are not willing to do the bidding or have fallen out with the leadership of the military and the civil service.
Ultimately this also leads to the disruption of the constitutional process when in 1958 the President of Pakistan, in conjunction with the Army Chief, General Ayub Khan, decides to abrogate the constitution and this of course leads to first Isknader Mirza overthrowing the constitution. And a few weeks later, Ayub Khan overthrowing Iskander Mirza.
Once there is military rule in the country, then any hope that the Eastern wing might’ve had for fair play or for due representation is no longer there. There are of course elections that are held under Ayub Khan’s military government, such as the 1964 election, but in those elections, universal franchise is denied because of the Basic Democracies, there is massive rigging that leads to a very predictable outcome and Fatima Jinnah defeated by Ayub Khan in the 1964 presidential elections. So, by the mid-1960s people in East Pakistan have realized that they cannot win through any fair political process. And this of course sets the stage for the radicalization of opinion in the eastern wing and the articulation of Mujib Ur Rehman’s radical six points which would turn Pakistan into a very loose confederation, if adopted.
These political factors were reinforced by very important economic trends. In British India, the revenue share of the provinces and the central government was about even, roughly 55-45, in the late 1930s. After Pakistan comes into existence, the central government federalizes most of the revenues leading to a situation where the central government is collecting 90% of the revenues and the provinces are getting only 10%.
The problem from the perspective of East Pakistan was that they were producing much of the country’s foreign exchange and also producing much of the country’s revenues. However, they got far less in return for their revenue contributions. In fact, between 1948 and 1961, around 80% of federal government expenditure and 70% of all development expenditure took place in the western wing of the country. And this was in spite of the fact that the eastern wing was responsible for Pakistan’s positive balance of trade, foreign exchange and earnings and contributed a larger share of the total revenue. So, there was a growing sense of alienation in the eastern wing owing to the economic policies, which as they saw it, were draining resources from East Pakistan for the purpose of investing them in them western wing.
This is also seen in terms of the divergence in per capita income. By the 1960s, West Pakistan was enjoying a per capita income of about 20% to 30% more than the eastern wing. And it was also enjoying much faster economic growth rates.
Then we can also come to certain military causes and particularly important in this regard is the 1965 War. Until 1965, Pakistan’s military leadership said that the defense of East Pakistan lies in the west. And what they meant by this was that in the event of a military conflict with India, West Pakistan, with its heavy concentration of military power, will be able to effectively neutralize India’s superiority on the eastern border i.e. East Pakistan. When the war happened, West Pakistan was barely able to defend itself and East Pakistan was left completely defenseless. This is one of the reasons why in his six points Mujib also wanted there to be a separate military force for East Pakistan and for the naval headquarters to be shifted there as well. This doctrine was exposed as unviable owing the 1965 war. But Pakistan’s military leadership and its political leadership did not actually rethink their strategic policy.
https://youtu.be/uay2x-7QcWU
All of these factors contributed to the alienation of the eastern wing. The disruption of the democratic process, the denial of the democratic majority of East Pakistan, the various unconstitutional interventions in Pakistan’s politics that further deprived the political leadership of its role in government and the economic causes that created inequality i.e. West Pakistan was getting wealthier as compared to East Pakistan using the resources that East Pakistan was providing. All of these came together and contributed to growing disaffection in the country.
The Ayub Khan military regime was unable to cope with the rise of left-wing populist parties like the People’s Party in the west and the Awami League in the east. However, rather than stepping down and handing over power to the national assemble, Ayub Khan stepped down and handed over power to Yahya Khan, who was the Army Chief. He then takes over as Chief Martial Law Administrator (CMLA) and as the President of the country.
Now, as the CMLA and as the president of the country, Yahya Khan presents himself as a popular figure who’s going to make concessions to the popular sentiment in the country. What does he do? He does away with One Unit, abolishes inter wing parity, declares that there will be fresh elections on the basis of universal franchise and he promises that in the next constituent assemble that he will convene there will be a simple majority provision through which the constitution bill would be approved.
Yahya and his advisors were of the view that the elections, if they take place, would have a highly fracture outcome. That is one of the reasons why they didn’t meddle too much in the electoral process. However, once the votes were counted and the results were out it became clear that the Awami League had emerged as the majority party with about 160 seats while in the west, the People’s Party had emerged as the single biggest party with more than 80 seats.
Faced with this situation, the logical step would have been to convene a meeting of the National Assembly. However, if a meeting of the Assembly was convened, then Yahya Khan’s earlier provisions, a simple majority would be enough to pass constitutional changes, would mean that the Awami League would be able to have its way. This set the stage for the final crisis of secession for the eastern wing because political parties in the western wing refused to participate, in large measure, in a National Assembly where they would have no role. The military was able to use this as an excuse to launch a crackdown on the 25th of March, 1971.
Once the crackdown was launched, a humanitarian crisis was created, which gave India an ideal opportunity to not only arm and facilitate the opposition to the Pakistani government in East Pakistan, but it also allowed India to take full advantage of the humanitarian crisis due to the influx of refugees into Indian territory. To paint itself as a champion of humanitarian intervention.
When India finally intervened militarily to end the East Pakistan crisis and end Pakistan’s control there, the international response was very limited and all of the major powers, including the Soviet Union and the United States, accepted the change in the realities on the ground. Leaving Pakistan, as far the United States is concerned, out in the lurch.