In 1975, the Church Committee (named after Frank Church), came to these conclusions.
The final report of the Church Committee concluded:
Too many people have been spied upon by too many Government agencies and too much information has been collected. The Government has often undertaken the secret surveillance of citizens on the basis of their political beliefs, even when those beliefs posed no threat of violence or illegal acts on behalf of a hostile foreign power.
The Government, operating primarily through secret informants, but also using other intrusive techniques such as wiretaps, microphone "bugs", surreptitious mail opening, and break-ins, has swept in vast amounts of information about the personal lives, views, and associations of American citizens. Investigations of groups deemed potentially dangerous -- and even of groups suspected of associating with potentially dangerous organizations -- have continued for decades, despite the fact that those groups did not engage in unlawful activity.
Groups and individuals have been harassed and disrupted because of their political views and their lifestyles. Investigations have been based upon vague standards whose breadth made excessive collection inevitable. Unsavory and vicious tactics have been employed -- including anonymous attempts to break up marriages, disrupt meetings, ostracize persons from their professions, and provoke target groups into rivalries that might result in deaths.
Intelligence agencies have served the political and personal objectives of presidents and other high officials. While the agencies often committed excesses in response to pressure from high officials in the Executive branch and Congress, they also occasionally initiated improper activities and then concealed them from officials whom they had a duty to inform.Governmental officials -- including those whose principal duty is to enforce the law --have violated or ignored the law over long periods of time and have advocated and defended their right to break the law.
The Constitutional system of checks and balances has not adequately controlled intelligence activities. Until recently the Executive branch has neither delineated the scope of permissible activities nor established procedures for supervising intelligence agencies. Congress has failed to exercise sufficient oversight, seldom questioning the use to which its appropriations were being put. Most domestic intelligence issues have not reached the courts, and in those cases when they have reached the courts, the judiciary has been reluctant to grapple with them.
After 911, with all the new technologies, they are probably worse.