June 15, 2026 The Honorable Markwayne Mullin Secretary United States Department of Homeland Security Dear Secretary Mullin: We write to you again, following up on our letter from May 21, 2026. We are six former superintendents and a former deputy superintendent of Big Bend National Park, with over 250 collective years of National Park Service (NPS) experience. In our previous letter, we urged you to reject the waiver of federal laws that would …