In federal or multi-jurisdictional law systems there could exist conflicts between the varied lessen appellate courts. Sometimes these differences is probably not resolved, and it could be necessary to distinguish how the regulation is applied in one district, province, division or appellate department. These past decisions are called "case law", https://riverzyrmi.wizzardsblog.com/39254140/the-single-best-strategy-to-use-for-pld-case-laws-on-terrorism-pdf