This amendment addressed the question of CIA and Defense Department covert actions, and prohibited the use of appropriated funds for their conduct unless and until the President issues an official "Finding" that each such operation is important to the national security and submits these Findings to the appropriate Congressional committees — a total of six committees, at the time, growing to eight committees after the House and Senate "select committees" on intelligence were established.
The legislation was meant to ensure that the intelligence oversight committees within Congress were told of CIA actions within a reasonable time limit. Senator Hughes, in introducing the legislation in 1973, also saw it as a means of limiting major covert operations by military, intelligence, and national security agents conducted without the full knowledge of the president.
A series of troubling revelations started to appear in the press concerning intelligence activities. The dam broke on 22 December 1974, when The New York Times published a lengthy article by Seymour Hersh detailing operations engaged in by the CIA over the years that had been dubbed the "family jewels." Covert action programs involving assassination attempts against foreign leaders and covert attempts to subvert foreign governments were reported for the first time. In addition, the article discussed efforts by intelligence agencies to collect information on the political activities of US citizens.
These revelations convinced many Senators and Representatives that the Congress itself had been too lax, trusting, and naive in carrying out its oversight responsibilities.
The first legislative response was enactment in 1974 of the Hughes-Ryan Amendment to the Foreign Assistance Act of 1961. In 1978 Congressman Leo Ryan, an author of the Hughes-Ryan act, was assassinated in Guyana, just prior to the Jonestown massacre of the Jim Jones colony.
The passage of the act posed four fundamental implications for executive power as it relates to covert action. First, the Act established ultimate accountability of the President for all covert action conducted by the CIA. As a result, this removed most vestiges of "plausible deniability" on the part of the President in case the action were to be exposed to the public or political rivals. Third, the act fundamentally expanded circle of "witting" persons in Congress -- leading to a dramatically higher risk of exposure through leaks in the event of Congressional opposition. Fourth, assuming these three features stand, the passage of the Act created both de facto and de jure Congressional veto power. This power could be used consitutionally, whereby the Congress could simply refuse to fund the covert action in question, either through withholding of funds or through leaking the issue to the press.