Senator Barbara Boxer ran for re-election and defeated Republican former Secretary of State Bill Jones.

Boxer originally had planned to retire in 2004 but changed her mind to "fight for the right to dissent" against conservatives such as House Majority Leader Tom DeLay.

Boxer portrayed Jones as too conservative for California, citing his votes in the California Assembly (1982 to 1994) against gun control and an increased minimum wage, and in support of offshore drilling and a loosening of environmental regulations.

[7] The election was not close, with Boxer winning by an authoritative 20 point margin.

[11] Boxer won 36 of 53 congressional districts, including three that elected Republicans.