Aside from the question of how judicial bias is measured, Caperton spotlights the larger question of whether choosing judges by popular vote is sound policy. In recent times, judicial elections have become high profile, big money political events much different from the quiet, low key affairs of earlier times. Choosing judges by popular vote on its face seems like an exercise in democracy but in practice judicial elections call out for reforms to rein in out-of-control judicial campaigns and to prevent litigants from buying judges through campaign contributions to cast votes in their favor. Imagine filling the current US Supreme Court vacancy by judicial election rather than appointment and Senate confirmation.
The BLS Library has in its collection some worthwhile material on the subject of disqualification of judges including an electronic resource entitled Fair Courts: Setting Recusal Standards by James Sample, et al., Call #KF8861 .S26 2008 (INTERNET) published by the Brennan Center for Justice at New York University School of Law, the legal team that represented the plaintiff in Caperton v.Massey. See also Judicial Disqualification: Recusal and Disqualification of Judges by Richard E. Flamm (Call # KF8861 .F53 2007).