Federal prosecutor John Keller, of the United States Attorney’s Office for the District of Arizona, may have a lot impact on the Mueller investigation and perhaps how long President Trump remains president. He gets a big say in whether to challenge President Trump’s pardon of Sheriff Joe Arpaio for criminal contempt of court.

Despite popular views in the media and among legal scholars, I don’t think the pardon of Sheriff Joe Arpaio is constitutional and here’s why: there is a huge separation of powers problem.

Simply put, the separation of powers in our government gives each branch of government – legislative, executive, and judicial, certain powers that the other branches are supposed to not interfere with – especially to the degree that they usurp the power of the other branch. President Trump’s pardon of Joe Arpaio undermines the United States District Court for the District of Arizona. US District Judge Grant Murray Snow’s judicial power to hold those who do not follow his lawful orders in contempt of his court has been functionally usurped – and that’s not cool.

Although Congress codified a process for the judiciary to follow to hold someone in contempt, the contempt power itself rests solely with the judiciary. Judges adjudicate cases. To do that they must have the ability to hold individuals who don’t follow their lawful orders in contempt of court. Other higher courts may weigh in on the legality of the order, but not the executive and not the legislature. The executive power to pardon for contempt of court is the power to destroy the judiciary. Can a president pardon all the people who just decided they didn’t like a court order?

So, how does it effect the Mueller investigation? The investigation is relying on the use of grand juries. The witnesses who plead the 5th Amendment can be taken from the grand jury to a judge where the prosecutor applies to the court for limited immunity for the witness, which is generally granted. Then the judge orders the witness to testify. Then when the witness disobeys a court order to testify - no federal crime, or civil fines or forfeitures, are involved at that point, but that witness does go to prison for contempt of court.

As aptly said in Re Nevitt, 54 C. C. A. 622, 117 Fed. 451, “...he [the person in contempt] carries the keys of his prison in his own pocket.” The contempt prisoner can be released at anytime by simply complying with the lawful order of the court. Or until they are pardoned?? Or maybe they can just not show up at all because they will be pardoned in advance for contempt of court??? How does Mueller, the judicial branch, and the rule of law enthusiasts like that?

Although, the U.S. Supreme Court has never ruled on the power of the president to usurp the judicial contempt power, the witnesses in prison may be in there a while until some court says otherwise. However, if the power of President Trump to pardon contempt prisoners is left standing, that may very well functionally impede, if not shut down, the Mueller investigation.

Remember, the list of potential Trump/Russia witnesses is long, and it is highly unlikely that its a list of true Trump loyalist heros. So many will never get as far as even risking contempt of court because they will talk – unless they feel assured that they will be pardoned. And I feel absolutely certain Trump will assure each and everyone of them of that.

Ball’s in your court U.S. Attorney Keller. A lot is riding on a successful legal challenge to this pardon – just the judicial branch’s autonomy, an undermined rule of law, and a radical right Supreme Court. No pressure.