The Crucial Question
Clearly, the crucial question is this: How do we determine which features of the precedent are needed to justify that decision? What we need to do is to extract a general rule of law that provides the best justification for the precedent decision.
The most obvious way to argue that a certain feature is important is to look at the written opinion in the precedent and see what the Court said— more specifically, what reasons it gave for its decision. In Yick Wo, the Court wrote:
whatever may have been the intent of the ordinances as adopted, . . . though the law itself be fair on its face and impartial in appearance, yet, if it is applied and administered by public authority with an evil eye and an unequal hand, so as practically to make unjust and illegal discriminations between persons in similar circumstances, material to their rights, the denial of equal justice is still within the prohibition of the Constitution.
Here the Court explicitly announces that the intent of the ordinance and its appearance (for example, whether the ordinance explicitly mentions race or ethnic background) did not matter to their decision. The Court also declares that it did matter that the ordinance in practice creates inequalities in rights. Such official pronouncements by a court have considerable force for future courts in legal arguments.
