California State Assembly (1978-82)

Bosco was elected to the California State Assembly in 1978 and was re-elected in 1980. In 1979 he wrote, with then-governor Jerry Brown, the Renewable Resources Investment Act, which set up a state fund to protect fisheries, forests, urban forests and the coastline.^[1][2] He served as a delegate to the 1980 Democratic National Convention and to the California Democratic State Convention in 1982.

United States House of Representatives (1983-91)

In 1982 Bosco won the Democratic nomination for California's 1st congressional district, which had been renumbered from the 2nd District after redistricting. Then, in a major upset, he defeated 20-year Republican incumbent Donald H. Clausen by just over two points. In Congress Bosco, an advocate of fishery and natural resource conservation, authored the California Wilderness Act and the Smith River National Recreation Area Act.^[3][4] In 1989, along with Barbara Boxer and Nancy Pelosi, Bosco co-authored legislation to preserve the Cordell Bank National Marine Sanctuary, protecting the coast of northern California from offshore oil drilling.^[5][6][7][8]

Bosco went on to serve four terms in the House, but lost in 1990 by 42%-43% (with 15% to a Peace and Freedom Party candidate) to Republican Frank D. Riggs, who in turn was defeated for re-election in 1992 by Democrat Daniel E. Hamburg. In 1994, Bosco attempted a comeback to his congressional seat by challenging Hamburg in the primary, but lost by 38%-62%.^[9] Hamburg went on to lose the general election to Riggs in a rematch, 47%-53%.^[10]