The ISI was reorganised in 1966 and expanded in 1969. During the rule of General Yahya Khan, the National Security Council (NSC) was formed to coordinate the functioning of Pakistan’s intelligence agencies. But the NSC is no more functional and the ISI is playing the role of coordinating the functioning of the country’s intelligence agencies.

In its initial years of formation, the ISI was seldom in limelight. Its main function was confined to interaction with the foreign Military Attaches accredited to Pakistan and supervising the working of Pakistani Military Attaches posted abroad.

It was with the growing involvement of the Pakistan Army during the days of Ayub Khan in Pakistani politics that the ISI’s role started expanding. The successive Martial Law regimes, beginning with that of Gen. Ayub Khan, strengthened the ISI to the detriment of other intelligence agencies, especially the Intelligence Bureau (IB), which was marginalised.

The ISI lost its importance during the regime of Zulfiqar Ali Bhutto, who was very critical of its role during the 1970 general elections, which triggered off the events leading to the partition of Pakistan and emergence of Bangladesh.

The ISI regained its lost glory after Gen. Zia ul-Haq seized power in July 1977, in late 1979, when the Soviet Union intruded into Afghanistan, Pakistan became a frontline state for the US and the ISI got a never - before boost. As Bhutto decided to cooperate with the US and other Western countries to contain the Soviet intrusion, the ISI played a pivotal role in channelising assistance for the Afghan Mujahideen.

The Soviet invasion of Afghanistan made Pakistan a country of paramount geostrategic importance. In a matter of days, the US offered to reopen aid and military assistance to this "frontline state". For the remainder of Gen. Zia’s tenure, the US generally ignored Pakistan’s developing nuclear programme.

By now, the ISI had acquired a halo of Pakistan’s top national security agency. It monitored the activities of and provided advice and support to the Mujahideen and along with SSG commandos of the Pakistan Army helped guide the operations inside Afghanistan. The ISI trained about 83,000 Afghan Mujahideen between 1983 and 1997 and despatched them to Afghanistan.

This action of the ISI, however, did not pass off without harm to Pakistan. Afghan and Soviet forces conducted raids against Mujahideen bases inside Pakistan and a campaign of terror bombing and sabotage was unleashed in Pakistani cities. These terror campaigns, guided by Afghan intelligence agents, caused hundreds of casualties.

In 1987, nearly 90 per cent of the 777 terrorist incident—recorded worldwide took place in Pakistan alone. The ISI continues to actively participate in the ongoing Afghan Civil War, supporting the Taliban, which has ousted the Rabbani government and now controls nearly 90 per cent of Afghanistan.

The ISI is tasked with collection of foreign and domestic intelligence, coordination of intelligence functions of the three military services, surveillance over its cadres, foreigners, the media, politically active segments of Pakistani society, diplomats of other countries accredited to Pakistan and Pakistani diplomats serving outside the country. Besides, the other charter of duties of the ISI is interception and monitoring of communications and the conduct of covert offensive operations.

The ISI has become a state within a state, answerable neither to the leadership of the army nor to the President or the Prime Minister. As a result, there has been no real supervision of the ISI and corruption, narcotics and big money have all come into play, further complicating the political scenario. Drug money is used by the ISI to finance not only the Afghanistan war, but also the proxy war against Bharat in Punjab and Kashmir.

The Joint Chiefs of Staff Committee deals with all problems bearing on the military aspects of the state security and is charged with integrating and coordinating the three services. Affiliated with the Committee are the offices of the Engineer-in-Chief, the Director General of Medical Service, the Director of Inter-Services Public Relations, and the Director of Inter-Services Intelligence. The ISI Directorate is of particular importance at the joint services level. Its importance derives from the fact that the agency is charged with managing covert operations outside Pakistan - whether in Afghanistan, Kashmir or farther afield.

The 1965 Indo - Pak war provoked a major crisis in intelligence. When the war started there was a complete collapse of the operations of all intelligence agencies of Pakistan as these agencies had been largely bogged down in domestic works such as tapping telephone conversations and chasing political suspects. Ayub Khan set up a committee headed by General Yahya Khan to examine the working of intelligence agencies.

Due to its deep involvement in domestic politics, the ISI has kept track of the incumbent regime’s opponents. Prior to the imposition of Martial Law in 1958, the ISI reported to the Commander-in-Chief of the Army (C-in-C). When Martial Law was promulgated in 1958 all the intelligence agencies fell under the direct control of the President and Chief Martial Law Administrator, and the three intelligence agencies - ISI, IB and Military Intelligence - began competing to demonstrate their loyalty to Ayub Khan and his government. The ISI and the MI became extremely active during the 1964 Presidential election-keeping politicians, particularly the East Pakistanis, under surveillance.

The ISI became even more deeply involved in domestic politics under General Yahya Khan, notably in East Pakistan, where covert operations were mounted to ensure that no political party should get an overall majority in the general elections. An amount of Rs 2.9 million was spent for this purpose and attempts were made to infiltrate the inner circles of the Awami League. The operation was a complete disaster.