The progressive American Constitution Society released a study finding judges tend to rule for members of their own party in deciding election disputes, and these effects are exacerbated by campaign donations. The report by Emory Law professors Joanna Shepherd and Michael Kang finds that “[j]udicial partisanship in election cases increases, and elected judges become more likely to favor their own party, as party campaign-finance contributions increase.” The authors also highlight that “[t]his influence of campaign money largely disappears for lame-duck judges without re-election to worry about.”
Another progressive organization, the Brennan Center, emphasizes two quotes from the study:
(1) “[i]f judges are influenced, consciously or not, by party loyalty in election cases, they are likely tempted to do so in other types of cases as well.”
(2) “reformers have advocated, among other things, public financing of state judicial campaigns; term limits for state judges; and various merit selection, judicial evaluation, and disciplinary systems,” and this study “bolster[s] the case for judicial selection reform.”
This study is valuable in providing data on the extent to which judges' politics matter to their rulings. However, progressives often err in thinking something like "elected judges are especially political so we should reduce the influence of judicial campaign money or, even better, replace judicial elections with merit selection." This is deeply wrong in several ways.
To some extent, judges should be political. Judges makes law. Lawmaking is part of their jobs, and has been for centuries, especially for high court judges. Lawmakers should, in a democratic society, be selected democratically. "Merit selection" is usually a euphemism for a method of judicial selection that violates the basic principle of democratic equality--the rule of one-person, one vote--by making a lawyer's vote worth more than another citizen's vote. "Merit selection" is a propaganda term for the nominating commission often known more-neutrally as the Missouri Plan. These commission systems often compound their violation of democratic equality by operating in secret so the commission's key vote is hidden from the public and accountability. Finally, Missouri Plan systems usually retain the problems of judicial elections because they usually subject sitting judges to retention elections.
Rather than the anti-democratic, secrecy, and campaign-contribution problems of the Missouri Plan, states should replace judicial elections with a judicial selection appointment process modeled on that found in the US Constitution. In about a dozen states governors nominate judges and they are confirmed by the senate or other popularly-elected body. This judicial appointment process selects judges with a form of indirect democracy, better for the rule of law than the direct democracy of electing judges.
As to judicial retention, the US Constitution gives federal judges job security which strengthens judicial independence compared to requiring judges to win elections to keep their jobs. States don't have to go as far in the direction of judicial independence as life tenure, as a long non-renewable term (say 14 or 20 years) would probably work about as well.