is remembered for testifying before the House Committee on Un-American Activities in 1948 about the penetration of the Soviet spy apparatus into the highest level of the U.S. government. He detailed his own involvement as a courier for the communists and fingered Alger Hiss - a friend, former State Department official and (at the time of Chambers' accusation) president of the Carnegie Endowment for International Peace - as a fellow operative.
The evidence against Alger Hiss was both shocking and undeniable: not only an employee of the federal government, but one who had access and influence in foreign affairs. In the course of revealing evidence against Hiss, Whittaker Chambers lost his career and reputation. Spies are useless, once they have revealed themselves in public. Chambers told about his activities in court, sacrificing his career in order to protect America from Communist spies.
Chambers was viewed as a hero who stood up under considerable pressure, in a sense destroying himself in order to witness to the truth about an inhuman system that had beguiled many.
Whether in the year 1948, or in the year 2011, systems like Communism and Socialism present themselves as viable and kind-hearted options. One must look past the rhetoric about helping one's fellow human being (who could argue against that?) in order to see that these systems are built upon flawed assumptions about human nature, and are doomed, despite any good intentions, to become ruthless tyrannies.