Bob Mueller has threatened President Trump and his legal team with a subpoena if he will not voluntarily submit to an interview.
But a subpoena is constitutionally unenforceable against a sitting president. This is clear from the section of the Constitution which discusses impeachment.
The power of impeachment to hold federal officials accountable in between elections is vested in Congress. The Founders’ Constitution makes it clear that no official of the central government is unaccountable, ever. A renegade president, for example, may be brought to heel through impeachment. He can be impeached by the House, the political equivalent of an indictment, and then may be convicted by the Senate, which acts as the jury, and, if found guilty, removed from office.
The president may be impeached for “Treason, Bribery, or other high Crimes and Misdemeanors.” “High crimes and misdemeanors” refer to political crimes, not just to legal crimes. They refer to major violations (high crimes) of his civic duties as an elected official. A president, in other words, can be impeached for things that are not necessarily criminal acts.
The provision of impeachment is there to provide accountability for the chief executive, but also to protect him from being drawn away from the duties of his office by becoming entangled in the ordinary legal process. Once his political opponents were to discover that they could tie him up in court over an endless succession of frivolous lawsuits, he’d never have time to devote to getting his job done. He’d effectively be crippled.
Here is the kicker. The president is exempt from getting sucked into the ordinary legal machinery unless and until he is actually convicted in an impeachment trial and removed from office.
This is clear from Article I, Section 3. The relevant paragraph reads as follows (emphasis mine):
Judgment in Cases of Impeachment shall not extend further than to removal from Office, and disqualification to hold and enjoy any Office of honor, Trust or Profit under the United States: but the Party convicted shall nevertheless be liable and subject to Indictment, Trial, Judgment and Punishment, according to Law.
In other words, if a president is convicted and removed from office as a result of impeachment proceedings, then and only then is he subject to the legal process of indictment and trial by jury. Until then, the legal system cannot touch him.
Now subpoenas are a part of the standard legal machinery in the U.S. court system. What all this means is that President Trump can ignore them because he has not been convicted in an impeachment trial.. Bob Mueller can issue all the subpoenas he wants, and the the president can ignore every one.
And he should ignore every one. The New York Times earlier this week published the list of questions Mueller wants to ask Trump, questions that are broad enough that they are intended clearly to create a perjury trap for the president. The president, of course, is garrulous to a fault, and this is what a desperate Bob Mueller is banking on.
Just as Christ’s adversaries kept trying to “catch him in something he might say” (Luke 11:54), so Mueller is hoping that the president will contradict himself in something he has said at another time and in another place. The president’s memory is famously fluid, and he is given to expansive statements and hyperbole. It’s a part of his style.
There is no upside to the president getting grilled by Mr. Mueller, and plenty of risk. Mueller knows there is no crime here, so he is trying to manufacture a process crime to get the president like he got General Flynn. There is no reason for the president to respond to a subpoena from Mr. Mueller, and plenty of reasons not to. The biggest of those reasons, thanks to the wisdom of the Founders, is found in the Constitution itself.