The prior ruling may have been followed as the law of the case, but there is a difference between such adherence and res [] judicata. One directs discretion: the other supersedes it and compels judgment. In other words, in one it is a question of power, in the other of submission

However, we reject the State's contention that either res judicata or the law of the case prohibits us from now addressing the legality of the membership goal.

In other words, "[l] aw of the case directs a court's discretion, it does not limit the tribunal's power."

For an example of Taft's willingness to require continuity of service with respect to property affected with a public interest

Res judicata bars the relitigation of issues in subsequent litigation, while the law of the case directs a court's discretion in the same litigation.

It is axiomatic that when a higher court "decides upon a rule of law, that decision should continue to govern the same issues in subsequent stages in the same case."