Appeals Court Judge Anni Foster, Maricopa County family court judge Julie Mata and juvenile court judge Michael Rassas all appear headed for defeat, even though each received a passing judicial performance review — the independent evaluation meant to give voters a factual basis for deciding whether to keep them.

It remains unclear why voters turned against the three judges. Conservative and progressive organizations alike published voter guides weighing in on the retention races, including the Maricopa County Republican Party and at least one progressive group.

Attorney David Rosenbaum said the involvement of political and interest groups carries a risk for judicial independence.

"That's one potential evil that a judge will realize that, wait, there's some interest groups looking over my shoulder every time I rule," Rosenbaum said.

He also warned that the prospect of being voted off the bench could deter qualified lawyers from leaving private practice to serve as judges.

Judges are barred from running conventional campaigns, and they may never learn why particular groups urged voters to remove them — a dynamic that leaves the bench vulnerable to campaigns waged entirely outside the courtroom.

Arizona is one of 19 states that use retention elections, in which voters cast a simple yes-or-no vote on whether to keep a judge in office. Nationwide, 38 states use elections of some form to select at least some of their judges, according to the Brennan Center for Justice.

The outcome in Arizona underscores a broader national debate over whether judges should be subject to political pressure at the ballot box, and what that pressure means for the fairness of the courts that residents rely on.