I have always been curious to know what the ultimate goal of the American legal system is — justice or truth? Which of the two virtues is more important in a society?
justice or truth?
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expediency wins every time.
“I have always been curious to know what the ultimate goal of the American legal system is justice or truth? Which of the two virtues is more important in a society?”
Neither one. The real goals are damage control and maintaining public order. Truth is often garbled, as the most sincere witness is imperfect in perception, memory and expression. Justice is never possible as no crime victim is truly made whole by any mortal court. People strive to do their best, but damage control and a relative degree of order is about the best that can be achieved.
The one with the most money.

“I have always been curious to know what the ultimate goal of the American legal system is justice or truth?”
I believe it is justice, I once read that in European law they do not have the adversarial system was have, and that a trial is more a collaberative “search for the truth”.