The Clarion Project's representatives testified before the Senate Committee on the Judiciary, providing expert testimony on the threats posed by Islamist extremism and the need for stricter immigration policies. Their testimony was cited in committee reports and policy discussions.

Leonard Leo has frequently briefed and lobbied members of the U.S. Senate Committee on the Judiciary, particularly during the Trump administration, to secure and advance the confirmation of conservative judicial nominees. His role involved providing insights on potential nominees, their judicial philosophies, and their alignment with conservative legal principles, while also coordinating testimony, mobilizing public support, shaping the narrative around key nominations, and coordinating with conservative legal organizations to influence the confirmation process. Leo's expertise and advocacy were influential and instrumental in shaping the committee's approach to confirming conservative judges.