A phrase that aims to preserve impartiality, as a judge would likely be swayed or otherwise affected if they were intimately involved in the issue at hand. It is a translation of the Latin legal maxim nemo debet esse iudex in propria causa. A: "My lawyers are seeking a mistrial in an attempt to get a different judge—one with no ties to my former company." B: "That's a good idea. No one should be judge in his own cause."