During his service in Washington, Lagomarsino specialized in environmental concerns, foreign affairs (particularly Latin America), and illegal drug trafficking. He authored legislation which created the Channel Islands National Park, the Dick Smith Wilderness Area, the Los Padres National Forest, and co-authored the Drug War Bond Act and the Violent Crime and Drug Control Act. He was a leader in efforts to open overseas markets to U.S. products and to ban transfer of strategic goods or technology. Lagomarsino maintained a voting record of 99% and took pride in voting against all proposed congressional pay raises.