Philosophically, Clarke demonstrated an affinity for legal realism in his opinions. He often voted with Oliver Wendell Holmes, Jr. and Louis Brandeis, usually in dissent from the conservative majority dominant on the Court at that time, though Holmes's famous dissent from the "Abrams v. United States" decision was in response to Clarke's majority opinion. As a Progressive, he supported the power of both national and state authorities to regulate the economy, particularly with regard to regulating child labor. His dissents on two cases, "Hammer v. Dagenhart" and "Bailey v. Drexel Furniture Company" supported Congress's authority under the Commerce Clause (in the "Hammer" case) and the Taxing and Spending Clause (in the "Bailey" case) to address what Progressives saw as a major social problem. He also demonstrated his opposition to monopoly in "United States v. Reading Company", in a ruling that became a prominent part of anti-trust law.