Although free expression is a central value in most democracies, it is hardly an uncomplicated ideal. One of the puzzles that freedom of speech presents is whether, and how, its tangible impact can be measured.

As a practical matter, what does speech actually do? In the American free-speech tradition, to borrow Harry Kalven's phrase (A Worthy Tradition, 1988), this question is a central tension. Many judicial initiatives to place purportedly necessary limits on speech have hinged on the actual or potential effects that speech produces. The common-law “bad tendency” test, the “clear and present danger test” announced by Oliver Wendell Holmes (Schenck v. United States, 1919), and the present-day fusion of clear and present danger with Learned Hand's “incitement test” (Masses v. Patten, 1919) all predicate their restrictions on speech by focusing on the actions and reactions of listeners, and the broader social harm that those reactions may engender.

The obvious long-standing problem, however, is that most of those reactions are purely speculative. The abovementioned systems of speech restrictions are often premised on what other people could do or might do in response to provocative speech. This abstract imprecision, combined with governmental instincts to crack down on any expression it does not like, can have a delegitimizing effect not only on specific speech restrictions but also on the broader theory that speech can cause actual injury.

In their own distinctive ways, two new books are meditations on this tension. Both Marc Lendler's Gitlow v. New York and the anthology of essays Speech & Harm, edited by Ishani Maitra and Mary Kate McGowan, explore the implications of effects-centered approaches to speech, and do so in intellectually invigorating fashion.

Lendler's monograph is the latest offering in the excellent Landmark Law Cases and American Society series from the University Press of Kansas, and it achieves the high standard realized by many of the books in this series. It tells the story of prominent Communist Ben Gitlow, a onetime member of the New York State Assembly who in 1919 was arrested and charged with violating New York State's Criminal Anarchy Law by publishing a pamphlet entitled “The Left-Wing Manifesto.” Although Gitlow himself did not write any of the material in the “Manifesto,” and although none of the material urged readers to commit any crimes, New York State argued that by having his name on the masthead of a publication that might have tempted a reader toward subverting the government of the United States, he was indeed liable for its publication.

The United States Supreme Court's eventual decision to uphold Gitlow's conviction occupies something of an odd place in the canon of American constitutional law. The Gitlow decision is seen as an important component of the line of free-speech cases decided by the Supreme Court in the aftermath of World War I, and it is invariably reproduced in textbooks designed for constitutional law courses at both the undergraduate and law school level.

Yet as a jurisprudential milepost, Gitlow is often overshadowed by its immediate predecessor cases from 1919—Schenck v. United States (which established the “clear and present danger test”) and Abrams v. United States (featuring a memorable dissent from the test's author, Oliver Wendell Holmes)—as well as by cases that come after it, such as Whitney v. California (1927) and its legendary concurrence from Louis Brandeis. Justifiably famous for its seminal announcement that the First Amendment's free-speech clause applies to the states, Gitlow's doctrinal approach to freedom of expression is often lost in the analytical shuffle.

Among this book's biggest achievements—and there are many—is how skillfully it fills in this record. Lendler's chapter on the development of free-speech law is brief, but in this economy of words, he is able to comprehensively trace the line from William Blackstone and “bad tendency” to the modifications put in place by the World War I cases and their progeny. Building on the work of scholars such as Leonard Levy (Origins of the Bill of Rights, 2001) and David Rabban (Free Speech in its Forgotten Years, 1870–1920, 1997), Lendler manages to analyze the nuances of this evolution at a high scholarly level, but does so in a readable manner that can be easily understood by undergraduates as well as more experienced readers who are newcomers to this subject matter.

The book's virtues are not confined to the exploration of legal doctrine. Equally impressive is Lendler's narrative of the trials of Gitlow and other communist contemporaries. The Gitlow case was but one in a litany of prosecutions of left-wing dissenters. The cases had similar results—all defendants were convicted—but wildly divergent styles. Gitlow used his case as a soapbox for tendentious dissemination of his political views, offering up a 15-minute statement that many observers suspected was allowed by a trial judge who was hoping that Gitlow, in his bombast, would tie his own noose in front of the jury. Other defendants such as Harry Winitsky refrained from pro-communist speechifying, but met the same ultimate fate. Lendler provides intriguing details from several trials, and in doing so transforms this project from a by-the-numbers report to a vibrant history.

Gitlow's biographical details also feature prominently, as Lendler documents his journey from dreamy communist firebrand to ferocious anti-communist critic. The peripatetic nature of Gitlow's public career, heavily influenced by internal Communist Party disputes, provides an enlightening backdrop to his case, and Lendler sketches Gitlow and other protagonists with a deft touch. Of special note are the author's descriptions of the variegated strategies that different lawyers employed in different cases.

If the book has a flaw, it is its too-quick and too-blithe chronicle of the Supreme Court's shift from a draconian view of free speech to the more expansive version urged by Holmes and Brandeis in their Gitlow dissent (and other opinions of the era). To explain that the Court eventually adopted the Holmes-Brandeis position, in part because new justices joined its ranks, breaks no new ground. A more satisfying treatment of this shift would have gone into more detail about how and why the Court moved in this direction, although it should be noted that space limitations for the books in this series may be an explanation for this omission.

The questionable legitimacy of the Gitlow prosecution hinges on the fatuity of the logic at its core: that by distributing this small newsletter, Gitlow could have generated a spark that in turn could have exploded into bloody revolution and national destruction at some later point. The editors of Speech & Harm, in comparison, embrace the possibility that certain kinds of speech do indeed produce devastating consequences.

Many of this volume's contributors postulate that speech does indeed directly inflict injury, and argue in favor of speech restrictions on these grounds. Some contributors, however, either question this assumption outright or grant the possibility but nevertheless argue that this does not justify speech restrictions. This diverse approach is one of the most attractive features of the volume, as is its interdisciplinary methodology. The contributors' expertise spans multiple academic disciplines, including philosophy, politics, law, and sociology. What could have been a narrow and one-sided volume is instead a rich and stimulating work that will challenge readers' preconceptions.

Another welcome attribute is the contributors' comparative focus. Although American free-speech principles are never far from the volume's analytical nucleus, a number of the contributors discuss how other nations handle such subjects as hate speech and Holocaust denial. Of particular interest here is Katharine Gelber's comparison of hate-speech regulatory regimes in the United States and Australia, along with Lynne Tirrell's chapter analyzing the implications of genocidal language in Rwanda.

Much of the work in Speech & Harm is influenced by the Critical Legal Studies and Critical Race Theory movements. Maitra's own chapter examining how speakers can subordinate listeners, transforming an audience into victims, is a worthy addition to this literature.

One of the best chapters is Laura Beth Nielsen's empirical assessment of one of the most basic notions that undergirds the American free-speech tradition: that the best response to offensive speech is to produce more speech as a counter, rather than to enact ordinances that shut down offensive speech. This posture was adopted by the various courts that were called in to adjudicate the controversy that erupted in Skokie, Illinois, in 1978, when a local band of neo-Nazis sought to march in a town populated predominantly by Jews, including many Holocaust survivors (see Phillippa Strum, When the Nazis Came to Skokie, 1978). The Gelber chapter, “Speaking Back,” with its call for a policy in which “the targets of hate speech are provided with the institutional, educational, and material support to enable them to speak back, both to contradict the messages contained within the hate speech and to counteract the effects of that speech on their ability to respond” (p. 51), is likewise a manifestation of the preference for “more speech” instead of preemptive censorship.

Nielsen, however, questions the efficacy of the “more speech” solution, and tested it by conducting an ethnographic study of multiple different-sized California communities. By means of more than a hundred interviews, Nielsen concludes that reliance on more speech as a counter to hate speech is a flawed rubric, owing mostly to the finding that most targets of hate speech simply silence themselves, falling back into a pattern of subordination similar to that outlined in Maitra's chapter.

Most of the material in Speech & Harm is top-quality work, although this standard is not uniformly met. Catharine MacKinnon's foreword, for example, reads less like an overview of the chapters to come and more like an exercise in personal score settling. Ultimately, though, the volume is highly recommended both for its superior writing and for its heterogeneous perspectives. It is written at a level that will be formidable for talented undergraduates, but more advanced readers will find it illuminating and informative.

The idea that speech can cause tangible damage to potential targets, once dismissed as nothing more than a rationalization for overarching official constraints on individual rights, is now gaining traction with the advent of new communications technologies. As these technologies become more widely adapted, emerging phenomena such as cyber-bullying will almost certainly lead to a reassessment of the basic principles that backstop freedom of speech. Such reassessment will be flawed without a full understanding of the history of how speech affects the audience, how it does (or does not) transform listeners/readers into victims, and how government has responded to these real or imagined problems. Together, Gitlow v. New York and Speech & Harm enable us to look backward for lessons that can be applied in the future.