What happens next in Trump’s immunity case?

A federal appeals court in Washington has now heard arguments on former President Donald J. Trump’s sweeping claim that he is immune from prosecution on charges of plotting to overturn the 2020 election.

The court has already moved the case along at an exceptionally brisk pace and is expected to make its decision fairly quickly by the standards of a typical appeal.

Here’s a look at what could happen once that decision comes in.

What happens after the appeals court rules?

If the appeals court decides in Mr. Trump’s favor, Jack Smith, the special counsel leading the prosecution, will almost certainly challenge the loss in front of the Supreme Court, assuming the justices agreed to hear it.

But the more likely outcome is that the three-judge panel rules against Mr. Trump, rejecting his claims of immunity.

At that point, he could seek to have the entire circuit court hear the appeal — a move that, if nothing else, would eat up more time. If the full court declined to take the case or ruled against him, he, too, would most likely ask the Supreme Court to step in.

What happens if it goes to the Supreme Court?

The Supreme Court had a chance last month to hear the case itself after Mr. Smith took the unusual step of asking the justices to leapfrog ahead of the appeals court. But even though they declined his request, it is likely they will have another shot.

At that point, the court in theory could decline to hear the matter altogether and simply let the appeals court ruling stand. That option could be appealing to the justices if they want to avoid stepping directly into a highly charged political issue — just one of several they are likely to confront that could have a bearing on Mr. Trump’s chances of reclaiming the White House.

Were that to happen, the case would go back to Judge Tanya S. Chutkan, who is handling the underlying case in Federal District Court in Washington, and she would begin to prepare for the trial, which is set to start on March 4. Her handling of the case so far suggests that she would move along at a rapid clip.

If, however, the Supreme Court were to take the case, the justices would have to make another critical decision: how fast to hear it. It is possible they could consider the case quickly and return a ruling on the immunity issue by — or even well before — the end of their current term in June.

But Mr. Smith has expressed concern in filings to the court that the justices might not be able to complete their work before the end of this term. If they do not, the case would drag into the next term, which does not get underway until October, too late to resolve before Election Day.

What does all of this mean for the start of the trial?

If the appeals court returns a quick decision against Mr. Trump and the Supreme Court lets that decision stand, the trial might be delayed, but perhaps only by a matter of weeks. Under this scenario, it is conceivable that the case could go in front of a jury by April or May, well before the heart of the campaign season.

If the Supreme Court takes the case and hears it on a fast-tracked schedule, the trial could be delayed for somewhat longer — perhaps by a matter of months. That would mean a trial could be held over the summer, a fraught possibility given that the Republican nominating convention is in July and that Mr. Trump, assuming he is the party’s nominee, could be kept from doing much traditional campaigning for the duration of the trial.

But if the Supreme Court takes the case and follows a leisurely pace in considering it, there might not be a trial at all before the general election in November. In that case, voters would not have the chance to hear the evidence in the case against Mr. Trump before making their choice — and a President Trump could try to make sure they never get that chance by attempting to order the charges to be dropped.