I do not believe a president can commit an obstruction crime by lawful actions that are within his discretionary authority under the Constitution — although I do not doubt that a president could be impeached for abusing his discretionary authority. (Concrete example: A president would not commit obstruction by mass-pardoning a category of dangerous offenders, but Congress could well decide that doing so was an abuse of power worthy of impeachment and removal.) But my view is hardly unanimous. Other analysts contend that ostensibly lawful presidential acts shed their legitimacy if corruptly motivated and therefore qualify as obstruction — i.e., as corrupt endeavors to influence official proceedings.
Who is right? That is a straight legal question of critical importance. Under federal law, the attorney general (or his deputy if, as here, the AG is recused) routinely delegates the OLC to prepare formal legal opinions for the purpose of guiding prosecutors and other government officials, and these opinions may be published for the benefit of the three branches of government, the bar, and the public. So why not let the OLC settle the matter?
An OLC opinion would be invaluable guidance for Deputy Attorney General Rosenstein and Special Counsel Mueller. An OLC opinion would help clarify whether there truly is a basis for an obstruction allegation against President Trump. This would either lift a cloud of suspicion that makes it very difficult for a president to govern, or put Trump and future presidents on notice of what seemingly lawful presidential actions carry the hazard of potential legal jeopardy.