There were a number of prime ministers between 1956 and 1958 and it reached a stage when General Ayub Khan felt the army should take control to restore stability.
Iskander Mirza had lost the support of many of the leading politicians and was alarmed at a plan by Suhrawardy to unite the political leadership of Bengal and Punjab against him.
Among the most controversial failings of the government were the continued uncertainly around canal water disputes causing a rift between the largely still agriculturally dependent economy of Pakistan's government and citizen farmers as well as the general geopolitical failure to adequately deal with the Indian threat to Pakistani Sovereignty in the disputed region of Jammu and Kashmir.
In the two-year period between 1956 and 1958, this turmoil saw four prime ministers - Chaudhry Muhammad Ali, Huseyn Shaheed Suhrawardy, Ibrahim Ismail Chundrigar and Sir Feroz Khan Noon -in rapid succession.
[1] A precedent existed in Pakistan whereby a Governor-General—in 1956 that office belonged to Malik Ghulam Muhammad before its powers were assumed by the president—could dismiss a prime minister and rule by decree until a new government could be formed.
[1] The quick succession of prime ministers as a result of Iskander Mirza's controversial actions fostered the view within the military that the public would support a coup against Pakistan's civil government and allow Ayub Khan to seize control of the country.
[2] He appointed General Ayub Khan, the Commander-in-Chief of the Pakistani army as the Chief Martial Law Administrator and nominated him to become the new Prime Minister of Pakistan, charged with administering the country.
In contrast, with future Pakistani military rulers such as Gen. Zia-ul-Haq and Gen. Pervez Musharraf, Ayub Khan did not seek to hold the posts of president and army chief simultaneously.