"The intelligence investigation under the leadership of Senator Church, which I know has helped cause this investigation by you, points out that the agencies did not disclose certain facts to us and that certain plots were going on"

The quote by John Sherman Cooper refers to the intelligence investigations led by Senator Frank Church, referred to as the Church Committee, which happened in the mid-1970s. This examination was a pivotal moment in U.S. history, as it uncovered considerable issues related to the operations of American intelligence firms, such as the CIA, FBI, and NSA, particularly regarding their secret activities and overreach.

Cooper discusses the "intelligence investigation under the leadership of Senator Church", which highlights the significance and the scope of the Church Committee's work. Established in 1975, the committee was tasked with examining abuses by U.S. intelligence agencies, partly in reaction to the Watergate scandal and other discoveries about government misconduct during that period.

The phrase "helped cause this examination by you" recommends that Senator Cooper is addressing another body or committee performing an investigation, potentially a congressional committee or subcommittee. This indicates the wider effect of the Church Committee in motivating additional examination and oversight of intelligence activities, and the need for transparency and responsibility in government operations.

Cooper notes that "the firms did not disclose specific realities to us", which underscores a substantial finding of the Church Committee: that intelligence firms had often acted without proper oversight or disclosure to chosen authorities, such as Congress. This lack of transparency had permitted specific unauthorized or morally questionable plots and activities to proceed unobstructed.

The mention of "certain plots" indicates the discovery of concealed operations, potentially describing assassination efforts, domestic surveillance, and other activities that emerged throughout these investigations. These findings raised severe ethical and legal questions about the extent of intelligence company power and precipitated reforms developed to safeguard civil liberties and make sure that such firms run within the bounds of the law, under the analysis of Congress and the public.