The pardon power of the President of the United States is the most narrowly tailored plenary power in the history of plenary powers. Its limits are inherent in the meaning of the word 'pardon.' No such thing as a 'preemptive pardon.' Don't cite Nixon/Ford. Facts are not same.

Nixon had a pending 'Articles of Impeachment' that would have turned into criminal indictments had he left office without a pardon for them. In that sense, they were not preemptive, as matters of impeachment hadn't yet been introduced in the House formally & were still ripe.

Donald's impeachment happened. No pending charges or any articles of impeachment with offenses that would turn into criminal indictments once he leaves office. So he can't pardon himself, not b/c self-pardon's moral & ethical heresy, but b/c he has nothing to pardon himself over.

About the pardons he has granted to people who were convicted of crimes related to the Mueller report: this pardon does NOT preclude a future DOJ from picking up the Mueller Report & prosecuting on other violations of federal criminal law that weren't previously prosecuted.

Depending on statutes of limitations of specific violated statutes, a future DOJ can & most likely will go after the same pardoned people for a whole different set of criminal offenses outlined in the Mueller Report. This includes un-indicted coconspirator AKA Individual One.