The immunity case was the last case argued, on April 25. So in one sense, it’s not unusual that it would be among the last decided. But the timing of the court’s resolution of Trump’s immunity may be as important as the eventual ruling.

By holding on to the case until early July, the justices have reduced, if not eliminated, the chance that Trump will have to stand trial before the November election, no matter what the court decides.

In other epic court cases involving the presidency, including the Watergate tapes case, the justices moved much faster. Fifty years ago, the court handed down its decision forcing…