This chapter explains how constitutional facts make up the rationale that is necessary in effective and responsible judicial review. First, facts can figure in the subject matter and standard of judicial review. When courts investigate the facts that underlie a legal provision, they make up the subject matter of judicial review. When they, instead, are investigated to determine the scope of a constitutional always need to be litigated in an adversarial setting and found. The only case where this is not so is when the constitutional fact is notorious, which requires proof and debate of its notoriety and not the fact itself. Second, in multi-member courts fact and evidence determinations ought to be made collegially, because individual judges cannot deprive their fellow colleagues from the materials seen as necessary to reach the merits and because the court needs to produce an opinion that can be seen as a coherent set of inferences and judgments supported on the facts and evidence that can justify the court’s final decision. Finally, the chapter argues that the complexities of constitutional facts may justify adopting differing standards of proof and the use of procedures to stimulate further debate by the people and their elected representatives.