Just one example of how fallacies are used in the legal system was in the OJ Simpson case.
In 1994 Simpson was accused of murdering his ex-wife Nicole Brown Simpson and her friend Ronald Goldman and tried by a jury in Los Angeles, California.
The location of the trial was especially critical in this case because the defense based their arguments to acquit Simpson upon the way the investigation had been conducted by the LA police department.
Simpson was acquitted by the jury, not because of his innocence or guilt, but because of past abuses committed by the LA police department. The process is called jury nullification. The fallacy used by the defense was IGNORATIO ELENCHI.
IGNORATIO ELENCHI is an irrelevant conclusion, one that is completely beside the point. To argue that constructing levees to contain flood waters is unnecessary because it isn't raining is beside the point. Other kinds of irrelevancies like red herrings (side issues) that attempt to divert the argument are included here. One might be the claim that, since a victim remained on the job, they wanted to be sexually harassed, or the rapist's defense that the victim wore a short skirt. Included also are diversionary tactics -- a lawyer's distracting the jury by flattering and amusing them or by diverting their attention from the guilt or innocence of the defendant to past inequities in the law, equality, opportunity, etc. The OJ case is a case in point.