McCain attacked what he saw as the corrupting influence of large political contributions—from corporations, labor unions, other organizations, and wealthy individuals—and he made this his signature issue. Starting in 1994, he worked with Democratic Wisconsin Senator Russ Feingold on campaign finance reform; their McCain–Feingold bill attempted to put limits on "soft money". The efforts of McCain and Feingold were opposed by some of the moneyed interests targeted, by incumbents in both parties, by those who felt spending limits impinged on free political speech and might be unconstitutional as well, and by those who wanted to counterbalance the power of what they saw as media bias. Despite sympathetic coverage in the media, initial versions of the McCain–Feingold Act were filibustered and never came to a vote.