Mechanics of reinstating previously overturned rulings

[MarkD]

I don't know what you mean about "mechanics." The only thing it takes for the Court to make any particular decision is for there to be a case in which a litigant asks the Court to render that decision.

I know of one example in which the Court overturned its precedent on a particular issue twice, with the third decision reinstating the first one. The issue was whether the federal government can impose its minimum wage law on state and local governments. In 1968 (Maryland v. Wirtz), the Court said yes, the Commerce Clause does permit the federal government to force state and local governments to pay the federal minimum wage. Eight years later, the Court reversed (National League of Cities v. Usery (1976)) and said that the Commerce Clause does not allow the feds to do that. Then nine years after that (Garcia v. San Antonio Metropolitan Transit Authority (1985)), the Court reversed itself again and concluded that the Commerce Clause does allow it.