Having recently left a position as a federal fraud and corruption prosecutor in Washington, D.C., to return to private practice, I have marveled at the many legal experts who have spent significant time debating whether a sitting president can be indicted and even what charges special counsel Robert Mueller may bring against President Trump. While these might be interesting legal questions, they are purely hypothetical. The Department of Justice (DOJ) has a longstanding policy stating that criminally prosecuting a sitting president is “unconstitutional.”  

That is a massively strong, mountainous statement, and the special counsel as a DOJ entity, subject to departmental policy and supervision, cannot overcome it.

{mosads}But the experts like to posit: maybe that DOJ policy position is wrong (it has not been tested in court), and so what if the special counsel went rogue? The problem there is that visible federal prosecutors do not go rogue in violation of DOJ policy. It does not happen.

Perhaps more critically, though, prosecutors such as Mueller, who gather evidence and thereafter only seek charges that they believe can stick all the way through trials and appeals, necessarily must face all practical realities and limitations. So here is a more practical, down-to-earth answer on charging President Trump: It is not going to happen. This is not a constitutional or politically motivated statement; it is a prosecutorial one.

Any prosecutor knows that reaching the top of the chain in a significant conspiracy (i.e., “collusion”) case is incredibly rare and that doing so requires the equivalent of a perfect game. A cooperator, or even a series of cooperators, is nothing more than a hitless first inning, given that humans are notoriously biased and unreliable. In the best of cases, a cooperating witness is a turncoat motivated to save his own skin. In the worst of cases — with which every prosecutor has dealt at some point — the witness takes the stand and is either too scared or confused to be believable, or denies critical facts or prior statements, leaving the government to impeach its own witness in a desperate attempt to save its case.  

Much has been made of the fact that some individuals have signed cooperation plea agreements in this investigation, but the reality is, those agreements do not tell us anything about what the people know or will say about Trump’s actions — and even if they have said Trump engaged in illegal acts, without significant corroborating evidence, those witness statements standing by themselves are essentially worth nothing in the decision to charge a case.

Given that flipped criminal cooperators are not enough, a prosecutor in a fraud or corruption case will, at a minimum, want strong and consistent documentary proof of both intent/knowledge and actions taken, and strong proof that the target individual is the one behind those documents. The difficult reality in significant organized conspiracy cases is that the boss at the top naturally does not leave a trail like this. If damning documentary evidence existed, the special counsel’s office undoubtedly would have found it — and likely would have taken some significant action by this time.

I doubt the special counsel would sit on incredibly clear evidence of crimes, the kind sufficient to bring criminal charges, and not at least prepare a report to Congress on an expedited basis to seek to relieve us of an active provable international conspirator on the job.  

While some folks might think that this president is the rare breed who could have recklessly left behind clear, uncontroverted evidence of corruption, prosecutors know that loose-cannon defendants present an even harder challenge. Intentions become very hard to establish when the mind of the actor is a demonstrably moving target.

Where cooperators and historical documentary proof fails, the gap sometimes can be filled with proactively obtained evidence through such means as surveillance, covert recorded conversations with cooperators or wiretaps. But in the case of Trump, the investigation is fully overt, and he is a sitting president who is surrounded by legal counsel. Proactive measures are essentially impossible here.

No remotely reasonable federal prosecutor would bring a case, much less a case against a top-of-the-chain boss, without a terrific answer to this question: How great is the evidence? In the case of the Russia investigation, it seems the evidence is not sufficient.

But do not just take my word for it. I have privately asked many seasoned, trustworthy prosecutors and federal agents whether they think any charges could result from this investigation. The nearly universal answer? No chance.

John Marston, a partner in Foley Hoag’s litigation department, is a former Washington, D.C., assistant U.S. attorney. He is an expert in government investigations, white-collar criminal defense, tax controversies and litigation. During his five years as a federal prosecutor, he served as first-chair trial attorney on more than 45 cases in U.S. District Court and Superior Court. Before going into private practice recently, he worked fraud and corruption cases in the D.C. District Court Grand Jury, which is where the Mueller investigation is being conducted.