Feingold's senatorial career began in 1992 with a surprising victory over Republican incumbent Robert Kasten. Feingold won the Democratic senate primary against two formidable opponents, then produced several offbeat political ads emphasizing Kasten's lack of availability to the people of Wisconsin during the general election. The nation was stunned by Feingold's victory, won on a pittance of campaign money. Kasten was as well; he broke into tears in his concession speech. Feingold, meanwhile, celebrated his victory in a high school gymnasium.
Senator Feingold is perhaps best known for his work alongside Senator John McCain on the campaign finance reform law, the Bipartisan Campaign Reform Act of 2002, known as the McCain-Feingold bill. He also supports issues such as health care reform, gay rights, education, AIDS prevention, environmentalism, a stronger foreign policy, senior citizens' issues, preserving Social Security, energy conservation, and abolishing the death penalty. Senator Feingold was the only senator to vote against the USA PATRIOT Act which he believes severely and unnecessarily limits Americans' civil rights.
He also voted against the Defense of Marriage Act which ultimately passed and which withholds marital rights from new residents who relocated from a state where same-sex marriages are allowed and has spoken out against the proposed Federal Marriage Amendment. In a prepared statement, he recognized victims and surviving partners of victims of the September 11, 2001 terrorist attacks who were in the audience and stated:
Senator Feingold regularly holds "listening sessions" in all 72 Wisconsin counties to listen to his constituents' concerns.