In provincial elections in East Bengal, the opposition United Front won an overwhelming victory, weakening the ruling Muslim League’s position in the eastern wing. The result increased elite fears that national politics could shift toward East Pakistan’s priorities. Those concerns helped push later proposals to reorganize the western wing as a single province for “parity” between the two wings.
Prime Minister Muhammad Ali Bogra’s government moved the “One Unit” idea from debate toward policy, arguing that merging West Pakistan’s provinces would improve administration and reduce regional rivalry. Critics, especially in Sindh, the Frontier, and Balochistan, warned it would centralize power and dilute smaller provinces’ autonomy. The plan also aimed to create a single western province to match East Pakistan politically.
After political maneuvering in the central government, Chaudhri Muhammad Ali was appointed prime minister. His cabinet prioritized finalizing a constitution and implementing the One Unit merger despite regional resistance. This leadership change mattered because it brought stronger executive momentum to the reorganization plan.
Pakistan’s Constituent Assembly passed the Establishment of West Pakistan Act, providing the legal basis to merge multiple western provinces, states, and territories into one province. This was the key legislative step that made “One Unit” operational, shifting authority away from the older provincial governments. The act set the stage for an official “appointed day” when the new province would take effect.
West Pakistan was formally created when the merger took effect, combining Punjab, Sindh, the North-West Frontier Province, parts of Balochistan, and several princely states into a single “mega-province.” The new provincial structure reduced the number of provinces in Pakistan to two: East Pakistan and West Pakistan. This administrative redesign became a central feature of Pakistan’s state-building during the late 1950s and 1960s.
In Kabul and other cities, rioters attacked Pakistani diplomatic missions after reacting to Pakistan’s incorporation of the North-West Frontier areas into West Pakistan. The violence reflected how internal administrative changes could also affect regional tensions, especially around Pashtun identity and border disputes. It showed that One Unit had consequences beyond domestic governance debates.
An indirect election created an interim provincial assembly for West Pakistan under the new One Unit setup. The assembly and provincial government structure were meant to administer the merged province while Pakistan continued working toward a permanent constitutional order. In practice, the new arrangement intensified debate about representation and whether smaller regions were being outvoted inside a large provincial legislature.
Pakistan’s first constitution came into force, recognizing only two provinces—East Pakistan and West Pakistan—and setting equal representation (“parity”) between the two wings in the national legislature. Because East Pakistan had a larger population, parity became a major point of political grievance. The constitution linked One Unit to national power-sharing and made the provincial merger central to Pakistan’s constitutional design.
Within the One Unit system, the West Pakistan provincial assembly passed a resolution urging the center to undo One Unit and bring back the four provinces. This signaled that opposition was not limited to street politics—it had entered formal institutions. The resolution also highlighted how difficult it was to maintain a single western province when major regions continued to demand autonomy.
President Iskander Mirza dissolved elected bodies, abrogated the 1956 Constitution, and proclaimed martial law nationwide, appointing General Ayub Khan as Chief Martial Law Administrator. This ended the brief constitutional-parliamentary period and shifted authority toward military-backed executive rule. The change mattered for One Unit because decisions about provincial structure increasingly depended on the military regime rather than representative bargaining.
Under Ayub Khan, a new constitution introduced a presidential system and maintained parity between East and West Pakistan, keeping West Pakistan as a single province. Legal protections made it harder to alter provincial boundaries, reinforcing the One Unit arrangement. This preserved central control but also kept alive regional complaints about representation and provincial rights.
A nationwide protest wave, including a major uprising in East Pakistan, weakened Ayub Khan’s rule and contributed to his resignation. Political demands increasingly centered on autonomy and fair representation, putting the One Unit model under greater strain. The crisis created the opening for Pakistan’s next government to change the provincial map and election rules.
President Yahya Khan issued the Legal Framework Order (LFO), setting rules for Pakistan’s first direct general elections and ending the One Unit province of West Pakistan. The order restored the four western provinces—Punjab, Sindh, Balochistan, and the North-West Frontier Province—reversing the 1955 merger. This marked the formal closing of the One Unit era and a shift toward province-based representation ahead of the 1970 election.
One Unit policy and the creation of West Pakistan (1955–1970)