“Citizens United” is the short-hand name for the controversial 2010 decision by the US Supreme Court . That ruling concluded that campaign contributions are a form of protected speech under the First Amendment, even when they are made by corporations and other large organizations. The backlash against Citizens United includes a broad campaign to overrule it through a nationwide constitutional amendment, an effort that is also focusing on local elections in Sonoma County this fall.
You can find those Sonoma County candidate responses here.
The national candidate response page is here.