The stretch between Election Day and Inauguration Day could be marked by escalating confrontation between President Trump and Special Counsel Jack Smith. A prison sentence for the possible president-elect could also upend the transition.

The prosecutor and the 45th president both appear to be locked into defiant postures. Trump has said that he would fire Mr. Smith “within two seconds” of taking the oath of office on January 20. The special counsel has indicated that he would continue to press the Mar-a-Lago and January 6 cases as long as he could.

Mr. Smith, who pushed to try Trump before the election, appears to be planning to prosecute until being ordered to stand down. CNN reports that “more than a half dozen people who are close to the special counsel’s office or other top Justice Department officials … believe Smith doesn’t want to close shop before being ordered to do so or being pushed out by Trump.”

A victory for Trump would transpose him to a commanding position in respect of the prosecutions arrayed against him. Department of Justice policy mandates that the “indictment or criminal prosecution of a sitting President would unconstitutionally undermine the capacity of the executive branch to perform its constitutionally assigned functions.” The Supreme Court in Trump v. United States showed itself alert to intrusions on the “unrivaled gravity and breadth” of the president’s duties.  

That guidance was first issued in 1973, during the legal pursuit of President Nixon. It has been reaffirmed in the decades since, with the Office of Legal Counsel reasoning that “an impeachment proceeding is the only appropriate way to deal with a President while in office.”

This means that even if Mr. Smith managed to keep his job, the cases he has brought would likely be frozen until at least 2029.

The Department of Justice, though, has never had occasion to discern whether the prohibition on prosecuting a sitting president extends to a president-elect. 

Trump, in the election interference case, has argued to Judge Tanya Chutkan that his prosecution as a candidate touches on what Justice Antonin Scalia once called “the boldness of the president.” Judge Chutkan has ruled that Trump’s run for office conveys no “legally cognizable” privileges. A president-elect, though, could plausibly make a stronger claim for protection.  

If the 45th president is successful on Tuesday, he would soon be vested with the power to appoint an attorney general who could then in turn fire Mr. Smith — or try to. The special counsel regulations require “good cause” to fire a prosecutor like Mr. Smith. The moment Trump takes the oath of office he would also be invested with the pardon power and thus would “have Power to grant Reprieves and Pardons for Offences against the United States.”

That grant of power — the court in Trump called it within the “conclusive and preclusive” authority of the president and therefore entitled to “absolute” immunity — would take hold starting only on January 20. Mr. Smith’s cases before Judge Chutkan and the 11th United States Appeals Circuit could chug along for months until Trump moves into the White House. The ultimate decision about whether to press forward or pull back during this interim period would likely be made by Attorney General Garland or President Biden. 

Even if Trump is triumphant at the ballot box, Judge Juan Merchan of Manhattan will hand down two rulings later this month that could upend the transition period. First, he is set to determine whether the Supreme Court’s determination that official presidential acts are presumptively immune ought to disturb Trump’s 34 state convictions secured by District Attorney Alvin Bragg. Then, he is set to hand down Trump’s sentence, which could include time in prison.

Trump would likely immediately appeal his sentence, and could be at liberty while that request for review made its way up the Empire State appellate ladder. He could not erase it, though, via the pardon power, because state crimes are not — at least according to long tradition — “offenses against the United States.” Still, a Trump win against Vice President Harris could also shake the case that centered on the adult film star Stephanie Clifford, known as Stormy Daniels. 

Judge Merchan, who has evinced skepticism toward Trump, could take a possible election victory into account when he delivers his sentence. That order was originally scheduled for September, but the jurist pushed it back. He could reckon that there is little chance, were Trump to again win the presidency, of him ever seeing the inside of a prison cell. That would likely require intervention from the Supreme Court, who could cite the Constitution’s Supremacy Clause to stay New York’s hand. 

That section of the parchment ordains that when federal and state law conflict, federal law triumphs. The Nine could reckon that the Constitution’s command that the president “take care that the laws be faithfully executed” could be frustrated by the confinement of a president — or president-elect — behind bars.