Mario E Diaz & Associates has extensive knowledge of homeland security issues and relationships with key members of the Department of Homeland Security. The firm helps clients in their work in such areas as border issues, transportation safety and many other related arenas. The firm also enjoys excellent relationships with key members of the Department of Homeland Security. Homeland Security Secretary Janet Napolitano is a former client of the firm, and her staff includes a number of individuals whom Mario E Diaz & Associates have worked with professionally and know on a personal level.