Final answer:
In standing by precedent, a judge relies on the principle of stare decisis.
Step-by-step explanation:
When a judge relies on the principle of precedent, they are standing by the decision made in previous cases. This principle, known as stare decisis, is Latin for 'to stand on the decision.' The judge looks for similarities between the current case and past cases and applies the rule of law from those earlier cases to the current one. Precedents help guide and justify the judge's decision.