Presidential signing statements—a written statement presidents attach to a bill when signing it into law—has recently come to light as a powerful, and possibly unconstitutional, tool for enhancing power of the unitary executive. Recent research has assessed how these signing statements have been used and why, offering insight into the politics of the American presidency in enacting public policy. This study examines how presidents use the signing statements as they approve legislation related to criminal justice, assessing them by type, president, and party affiliation. Results suggest support for the unitary executive theory and that presidents often take a unilateral action approach in their use of signing statements—including those that potentially violate the U.S. Constitution.