The Federal system in Pakistan has come under increasing regional pressure ever since independence.
First of all, federalism did not exist in Pakistan in its true sense as the Centre was too powerful, which created a lot of resentment mostly from small provinces who wanted regional autonomy. Regionalism, an opposition to the highly centralized federation, was also opposition towards the One Unit Act which denied the small provinces a say in the affairs of the country. This strong Centralisation reached its climax during Ayub’s rule as the Presidential constitution of 1962 further strengthened the grip of the Central government over the two provinces and increased Ayub’s powers. Things should have changed with the 1973 constitution which granted regional autonomy but Bhutto increased his grip by making amendments in the constitution which decreased the powers of the judiciary and the assembly. Thus, the undemocratic authoritarian rules of Bhutto and Ayub resulted in resentment and pressure towards the Centre to increase.
Another reason why federalism didn’t work out the way it should have was the ethnic and linguistic differences. Pakistan is too diverse and many a times there was an outbreak of crisis between the provinces and the Centre or the provinces