[gbrown]

In principle, the adversarial system of justice in the United Systems is supposed to sort of work in this way (though the judgement is by a third party). Even though each party is focused on winning, the structure is supposed to give rise to fairness by construction.

Whether that happens in practice is... debatable.

[CobrastanJorji]

A better example might be an inquisitorial justice system, in which a theoretically neutral party attempts to reach a conclusion and a defensible support for it.