It is probably well known that the judge decides the facts and the juror's determine the facts. Here are pointers to a law review articles that showed that in the beginning of America, the jurors did decide the law. They then question the basis for this, since law is no longer the apolitical science.
Also, judges have the power to enter a summary judgment. This prevents a trial. This is done when the judge finds that the law commands the case and there is no legitimate dispute over the facts. E. G. the plaintiff might submit a duly signed contract for a sale and state that it sent the money but never got the goods. If the defendant doesn't deny, beyond a scintilla of evidence, that these facts are true, then the plaintiff gets a summary judgment. NO trial, no jury. Apparently the Federal Courts is increasing the number of times it does this.