President Donald Trump began his week with a statement that, while amounting to fewer than 280 characters, conveyed an astonishing threat to the American rule of law. “As has been stated by numerous legal scholars,” he tweeted on Monday morning, “I have the absolute right to PARDON myself.” In short, he was declaring that he could commit federal crimes and effectively get away with it.

Whether a president is allowed to pardon himself is an open legal question. In the final days of the Watergate crisis, the Justice Department’s Office of Legal Counsel concluded in a memo, “Under the fundamental rule that no one may be a judge in his own case, the President cannot pardon himself.” But OLC opinions, as influential as they may be, are not conclusive judicial rulings. The Supreme Court has never ruled on the matter because none of Trump’s predecessors attempted so brazen a move.

While some observers have predicted that a self-pardon would be reviewed by the court, the path to the justices’ doorstep is more complicated than it looks. To trigger a legal battle, federal prosecutors would likely need to charge Trump with the crimes for which he pardoned himself, then argue before the courts that the pardon was invalid all along. But since Justice Department guidelines have ruled out prosecuting a sitting president, that face-off likely wouldn’t occur until after Trump leaves office in 2021 at the earliest, if it happens at all.

A more likely pathway to the Supreme Court, for now, is through the tug-of-war over whether Trump will submit to an interview with special counsel Robert Mueller. Trump’s lawyers have indicated they’re still working with Mueller to come to an arrangement, but if those talks fail, the special counsel may well subpoena Trump to appear before a grand jury—in which case a Supreme Court showdown would be likely.

Mueller reportedly first signaled that he wanted to interview the president last December, in one of his regular meetings with Trump’s lawyers. Trump has publicly said he’d be willing to do it. But his lawyers and other allies have bristled at the idea of placing the president in Mueller’s direct path. Rudy Giuliani, Trump’s media-friendly lawyer, recently described a potential interview as a “perjury trap.” Though he apparently meant it as a critique of the special counsel, it actually says more about his client’s habit of telling lies. After all, it’s only a perjury trap if you commit perjury.