"As a member of the House Un-American Activities Committee, Richard Nixon led the investigations that first drew attention to Alger Hiss and his purported ties to the Soviet regime. These investigations eventually led to the discovery of "proof" that Hiss was a mole in the State Department and precipitated a trial that would eventually ruin him and propel Nixon to the Presidency. But what if the "proof" that eventually led to Hiss's conviction was...