A decision from an appellate court is binding on courts beneath it in the same jurisdiction when those courts decide similar issues. But your case law research does not end simply because you've found an appellate court case that appears to support your argument. Even a case directly on point may lose its authority if

1. The decision is reversed, vacated, or remanded on appeal
2. The decision is overruled, limited or otherwise called into doubt in by other cases outside the case's appellate history
3. The decision is rendered moot by subsequent legislation

It is therefore necessary to verify the validity of any case you cite by checking its history and finding other cases that have cited it. Only after doing so can you be assured that the cases supporting your argument are good law. KeyCite, Westlaw's citation checking service, is as current and comprehensive as Westlaw.