Testimony before the Warren Commission of Alan Belmont, assistant to the director of the FBI (J. Edgar Hoover), in charge of all investigative work:

Mr. BELMONT: Our activities are directed to meet the terrific responsibility we have for the internal security of the country, but to meet it under the law. We feel that to place security as such above the rights of the individual or to increase these controls beyond what is absolutely essential is the first step toward the destruction of this free society that we enjoy. We have been asked many times why we don’t pick up and jail all Communists. The very people who ask those questions don’t realize that if action, unrestrained action, is taken against a particular group of people, a precedent is set which can be seized on in the future by power-hungry or unscrupulous authorities as a precedent, and which inevitably will gnaw away at this free society we have, and sooner or later will be applied to the very individuals who are seeking this action.

[This is somewhat hypocritical, given what Hoover was willing to do outside the law when it suited him, but still . . . things have changed since 1964.]