Robert Mueller, the recently appointed special counsel overseeing the criminal investigation into whether Donald Trump’s campaign coordinated with Russia, has a sterling reputation as a prosecutor’s prosecutor — someone who follows the facts without fear or favor, wherever they may lead. Based on what we know so far, those facts will lead him to the most consequential decision any American prosecutor has ever faced: Whether to pursue charges against the president of the United States for the federal crime of obstruction of justice.
Make no mistake, that is a decision that Mueller not only can, but must, make. According to his order of appointment, he is to investigate “any matters that arose” in connection with now erstwhile FBI director James Comey’s investigation into the Russian affair. That mandate includes an investigation into Comey’s own unprecedented ouster, ordered by President Trump on the heels of the now infamous Valentine’s Day tête-à-tête in the Oval Office, in which Trump urged Comey to drop the Russia investigation. Such interference by a president with an ongoing FBI investigation bears striking resemblance to the “smoking gun” that ended President Nixon’s presidency, and may well be grounds for Trump’s impeachment. But it could also be grounds for something else: a federal indictment for obstruction of justice.
Mueller’s job is to decide whether the facts and the law support such an indictment, and, if so, whether to file one. As far as the facts and law go, he must resolve three open questions:
First, did Trump’s conduct violate the federal obstruction of justice statute, which criminalizes interference with “any pending proceeding” being conducted by an “agency of the United States”? Courts have not definitively resolved whether that statute covers interference with an FBI investigation, as opposed to a more formal proceeding, such as an investigation by a grand jury or by Congress — although there’s an argument that Trump’s conduct sought to interfere with those two things as well, given the pending congressional hearings on Russia and the pending grand jury investigation of Michael Flynn.
Second, even if Trump did try to interfere with an investigation covered by the statute, there’s a question of whether he did so with an illegal purpose, a key element for establishing criminal liability. Lighting a fire in your backyard, for example, could be summertime fun, or it could be a felony, depending on whether your purpose was to roast marshmallows or to burn your house down for the insurance money. Similarly, a president, as chief executive of the federal government, might seek to direct or terminate a federal investigation for lawful or unlawful reasons. Determining a potential defendant’s true purpose is hard, and usually turns on circumstantial evidence, unless he confesses. But proving intent, even through circumstantial evidence, is not impossible. On the contrary, it’s something prosecutors have to do in almost every case. And according to some expert prosecutors, the evidence of Trump’s illegal intent is atypically strong.
Which raises the final question. Even if he committed a crime, is the president immune from prosecution while in office? No court has ever resolved this issue, which divides legal scholars, largely because the Constitution’s text and history don’t provide clear answers. Indeed, the question has even divided the Department of Justice, which has weighed in on the issue four times in the past 50 years. On three occasions, the department said the president is immune from prosecution while in office. But on the fourth, the department argued forcefully against presidential immunity — in a Supreme Court brief written by the special prosecutor in United States v. Nixon.
Mueller is now in a situation similar to his predecessor. He faces hard open questions with no certain answers. But here’s the kicker: Hard open questions routinely underlie criminal prosecutions. That’s why an indictment is followed by a trial, to give judges and juries a chance to resolve those questions, after hearing arguments from the prosecutor and the accused. The prosecutor’s job, under our longstanding laws and traditions, is not to avoid charges whenever some question might plausibly be raised about the case. Rather, his job is to make his best assessment of the suspect’s guilt, based on all the facts and all the legal arguments available. And if he concludes there is probable cause to proceed, his final and most important job is to decide whether he ought to do so, based on his own best judgment of the various competing interests and values at stake.
How Mueller should resolve these open questions of fact, law, and judgment is up for debate. How he will resolve them is anyone’s guess. But this much is clear: whether Donald Trump will become the first president to also be a criminal defendant is now, unavoidably, a decision Mueller must make.
Andrew Manuel Crespo is a law professor at Harvard University, specializing in criminal law and criminal procedure. He tweets @AndrewMCrespo