The whole question is really irrelevant, its just another bone Trump trows out to drive the left wing media bonkers.
The Constitution gives the president the right to pardon anyone, period. Some scholars might disagree that it may not mean he can pardon himself but the real argument about this is just an exercise in futility because the Constitution also makes it clear that the President can NOT be indicted criminally as President so there is no need for a self pardon.
The ONLY recourse against a sitting president is Impeachment and there is no pardon for that.
Mueller has no power to indict or charge the President with any crime, period!
kind of
“Judgment in cases of Impeachment shall not extend further than to removal from Office … but the party convicted shall nevertheless be liable and subject to Indictment, Trial, Judgment and Punishment, according to law.”
— Article I, section 9, U.S. Constitution
the IMPEACHMENT process can only remove the POTUS, but the POTUS is THEN still liable to the proper authorities according to the law.
so a POTUS can't be criminally charged while POTUS, but the removal from office allows for them to THEN be criminally charged.
Impeachment is the process by the House to charge a government official(is not specific only to the president) with a crime like in the case of Clinton who was charged with perjury and obstruction.
Then must go to the Senate to convict such official to remove them from office.
This takes 2/3 majority vote and is typically presided over by the Senate President(the Vice President) or the Chief Justice.
As in Clinton's case, he was in impeached but remained in office because as in most cases the Senate RARELY convicts.
So even if the best wishes of the far left Dems came true and the very slim possiblity Trump was ever "impeached" he would never be"convicted"and removed from office by the Senate and thereby would never face criminal charges,Period!