See more of the story

The appointment of a special counsel is always a tragedy, in the sense that going under the surgeon's knife is always a tragedy. Like the human body, the government should function smoothly without the need to slice and cut. The Justice Department brings in an outsider only when the public does not trust the executive branch to investigate itself. Even when, as now, there may be good reason for the mistrust, the moment is hardly one for celebration. Even when we know surgery is necessary, we do not throw parties.

So although I fervently hope that Robert Mueller will perform as admirably in the role of special counsel as he did in the role of director of the Federal Bureau of Investigation, I am not ready to turn handsprings. Like most of us, I would like to know the truth about any ties between Donald Trump's presidential campaign and the Russian government. But although Mueller is a man of unquestioned probity and determination, I have never much liked the idea of special counsels, even back in the days when they were appointed by the judiciary and called independent counsels, not least because the counsel is not really subject to any authority but his own. The investigation can range as widely as any particular individual holding the position might wish. Yet rarely do we learn the truth about the events the counsel was appointed to investigate.

The calling of the outsider to cleanse the Augean stables possesses a mythic quality. The hero, we think, will clear away the muck and mire, so that our governmental institutions will once more glitter with the bright, happy aura of democracy. But this is never what happens. Patrick Fitzgerald never prosecuted anyone for leaking to the press the fact that Valerie Plame was an analyst at the Central Intelligence Agency. Kenneth Starr, although we tend to forget the fact, was originally appointed to look into Travelgate, the details of which are long forgotten, and the Whitewater mess, which is barely mentioned in his final report. Put otherwise, there is little evidence to support the proposition that an outside investigator will do a better job than a prosecutor already employed by the federal government.

Like much that is done to please press and public, the selection of a special counsel partakes of magical thinking. Troubled by a bubbling scandal, impatient with the turning of the wheels of justice, we summon the mage in the hope that his powers will enable us to find the truth lurking in the murky depths — as if criminality constitutes the only true measure of political malfeasance, and prosecution the only means of learning the truth.

The defining myth of the special prosecutor story remains President Richard Nixon's dismissal of Archibald Cox in 1973 — a firing that hastened Nixon's fall from power — and hardly anybody who doesn't happen to have a keen interest in history remembers the identity of Cox's successor. Those of us who were of political age remember how the future of democracy seemed to hang in the balance as federal agents began to secure the ousted prosecutor's files. But that was more than 40 years ago, and the tale, through constant retelling, is now so firmly embedded in the American saga that no president since has dared interfere in the smallest way with the counsel's work. On the contrary: Nowadays, the special counsel, once appointed, is rarely quite called upon to be heroic.

In particular, the special counsel need not endure the "ordeal" that forms a crucial part of Joseph Campbell's model of the hero's journey. True, the outsiders summoned to investigate an administration are maligned by the president's partisans. Witness Starr and Fitzgerald, each never forgiven by half the country for their efforts during the presidencies of Bill Clinton and George W. Bush respectively. And President Trump, in a not-atypical show of vindictive bravado, has already dismissed Mueller's inquiry as a partisan "witch hunt." In Greek mythology, Heracles had to change the courses of two mighty rivers to clean the muck from the stables. That the special counsel must suffer criticism hardly compares. That's not a bad thing — but it does suggest that we should perhaps think less magically about the work that the outside prosecutor will perform.

History warns us to be cautious in our hopes. Mueller might uncover the smoking gun that supplies my friends on the left with their yearned-for impeachment; he might find, as my friends on the right hope, that there's no fire after all. Most likely he will follow his predecessors in convicting a few aides for lying to the grand jury, and issuing a report admitting that he has been unable to determine for certain what happened in the campaign.

And let us not forget that the special counsel is free to roam where he will. It may be too early for the Democrats to cheer. Just as the surgeon preparing to remove the spleen might discover that the real problem is in an adjoining organ, so might Mueller decide that he needs to cut elsewhere. Let's stretch our imaginations a bit. Suppose he were to decide that the FBI's handling of the controversy over Hillary Clinton's email server was so inept that the investigation must be repeated. There is nothing to stop him, should he think it necessary, from kicking over that particular stone. Yes, as a formal matter, Mueller must go back to the Justice Department for permission to widen the inquiry, but nobody imagines that this requirement constitutes a serious check on the prosecutor's authority. What Mueller asks, Mueller will get.

It is true that Trump has assured us that the email controversy is over, but the president's promise can hardly be taken to bind the special counsel. Otherwise any figure the special counsel targets might object that he, too, was promised by the chief executive that he would not face investigation. Nor is this prospect outlandish: One can readily imagine this strange president, in one of his many moments of reckless impulsiveness, offering some wayward campaign staffer exactly that assurance.

I do not mean to suggest that this scenario is likely. Still, the mere fact that it is readily imaginable should serve as an uncomfortable reminder of the breadth of discretion we vest in the heroes we summon to clear out the stables. Yes, the nation deserves to know about any ties between the Trump campaign and the Russian government. Alas, for all the qualities that make Mueller the right choice, nothing in recent history teaches that a special counsel is more likely than an existing prosecutor or a congressional committee to tell us.

Carter is a professor of law at Yale University and was a clerk to U.S. Supreme Court Justice Thurgood Marshall. His novels include "The Emperor of Ocean Park" and "Back Channel," and his nonfiction includes "Civility" and "Integrity."