But whether the talks fail or drag on, Mueller no doubt already has in his hand a signed subpoena ready to deliver. Like all federal grand jury subpoenas, it starkly directs: “YOU ARE COMMANDED to appear in this United States district court at the time, date, and place shown below to testify before the court’s grand jury. When you arrive, you must remain at the court until the judge or a court officer allows you to leave.”

The president’s team truly does not want to receive that subpoena. Witnesses enter the grand jury room alone, without a lawyer, and must answer the prosecutors’ questions unaided. While the president would be free to step outside the room to consult with counsel, it is the nightmare of Trump’s lawyers that they will be outside a room where he is being submitted to determined cross-examination. So no question, they will negotiate a compromise. Mueller will get his testimony.

Trump’s lawyers may also choose to litigate, both in hopes of achieving a Hail Mary court result, and in delaying the interview past Mueller’s July deadline. If so, they should recall that Bill Clinton’s efforts to delay his own inevitable grand jury testimony formed a key part of Count XI of Kenneth Starr’s recommended Grounds for Impeachment—so Trump might only be fueling the case for obstruction of justice by seeking a delay of his own.