The founding of Pakistan and the framing of its Constitution has entailed a long rocky road that has led to the gradual strengthening of the tenets of democracy in Pakistan.
The first Constituent Assembly of the country was formed in December 1945 in undivided India. After independence, this Assembly was assigned the task of framing the Constitution of Pakistan. On 12 March, 1949 the Objectives Resolution was passed, that lay the principles for the Constitution. This legislative body was however, dissolved in October 1954 before the constitution was framed.
In May, 1955 the Second Constituent Assembly was formed, which framed and passed the first Constitution of Pakistan on 29 February, 1956. Promulgated on 23 March the same year, this Assembly provided for a parliamentary form of government with a unicameral legislature.
The promulgation of Martial Law on 7 October, 1958, led to the abrogation of the Constitution. In February 1960 the military government appointed a Constitution Commission which framed the 1962 constitution that provided for a presidential form of government; which was once again abrogated on 25 March, 1969. The Civil Government, which came to power in December 1971, formulated an interim Constitution in 1972 with the help of a 25-member committee appointed by the National Assembly of Pakistan that prepared a draft of the permanent constitution. The team was headed by Mahmud Ali Kasuri. The draft bill for the constitution was signed by leaders of all parliamentary groups in the National Assembly on October 20, 1972. A bill to provide a constitution for the Islamic Republic of Pakistan was introduced in the assembly on February 2, 1973, which was passed on 12 April, and promulgated on 14 August, 1973. The 1973 Constitution provided for a parliamentary form of Government with a bicameral legislature, comprising of the National Assembly and the Senate.
The current membership of Senate comprises 104 members. Originally the membership of Senate was a mere 45 that was raised to 63, in 1977 and 87 in 1985. In 2002 the membership of Senate was once again raised from 87 to a 100. The Eighteenth Constitution Amendment) Act added four non-Muslim members to the composition of Senate, resulting in total membership of 104.
* 14 August, 1947 to 1st March 1956 the Government of India Act, 1935, was retained as the Constitution of Pakistan.