In his dissent in the Abrams case (November 1919), U.S. Supreme Court Justice Oliver W. Holmes coined the metaphor of a “free trade in ideas” to justify stronger free speech guarantees. This epistemic argument for free speech, later turned into the notion of a “marketplace of ideas,” became a powerful normative and interpretive rationale of expressive freedoms. However, before the Abrams dissent, Holmes was far from being a champion of free speech. As late as the spring of 1919, he had (...) upheld the constitutionality of repressive wartime legislation. Thus, the summer of 1919 is a major turning point in Holmes's views. This article focuses on the role of the young Harold Laski during these months, examining his book recommendations to the Justice. Insisting on the truth-seeking functions of expressive freedoms, Laski's books pointed argument which is found in the Abrams dissent. I also consider additional reasons for Holmes's change of mind, particularly how the “First Red Scare” affected Laski and other civil rights activists. Lastly, the article reflects on what the Laski-Holmes relationship may tell us regarding the later assimilation of the Abrams dissent and the “marketplace of ideas” as core elements of a long-term libertarian tradition of free speech. (shrink)