Judicial bias is a tricky thing. It shouldn’t exist, of course—donning a black robe should confer superpowers that remove all traces of prejudice from the human mind.

But in the real world, it’s not so simple. Which is why a complaint filed on Tuesday against a Kentucky judge by Lambda Legal, the American Civil Liberties Union, the ACLU of Kentucky, Kentucky’s Fairness Campaign and University of Louisville Law Professor Sam Marcosson raises some difficult questions.