Historians Caro and Dallek consider Lyndon Johnson the most effective Senate majority leader in history. He was unusually proficient at gathering information. One biographer suggests he was "the greatest intelligence gatherer Washington has ever known", discovering exactly where every Senator stood, his philosophy and prejudices, his strengths and weaknesses, and what it took to break him. Robert Baker claimed that Johnson would occasionally send senators on NATO trips in order to avoid their dissenting votes. Central to Johnson's control was "The Treatment", described by two journalists:
The Treatment could last ten minutes or four hours. It came, enveloping its target, at the Johnson Ranch swimming pool, in one of Johnson's offices, in the Senate cloakroom, on the floor of the Senate itself wherever Johnson might find a fellow Senator within his reach.Its tone could be supplication, accusation, cajolery, exuberance, scorn, tears, complaint and the hint of threat. It was all of these together. It ran the gamut of human emotions. Its velocity was breathtaking, and it was all in one direction. Interjections from the target were rare. Johnson anticipated them before they could be spoken. He moved in close, his face a scant millimeter from his target, his eyes widening and narrowing, his eyebrows rising and falling. From his pockets poured clippings, memos, statistics. Mimicry, humor, and the genius of analogy made The Treatment an almost hypnotic experience and rendered the target stunned and helpless.
