Question

Why do Justice Scalia and Justice Stevens both devote such large portions of their opinions to analyzing early American statutes and to reviewing the writings of the authors of the Constitution (the Framers)? Does an examination of his torical materials help the Court decide a case today?

Answer 1

America is a common law system, so you build cases and decisions by building the rationale for decisions on the arguments of Judges before you through the use of precedent.

So, Scalia and Stevens and others would want an argument to be based on the framers or previous decisions to show how established the idea is in American jurisprudence.