The President has no pardon or commutation power over state convicts such as Mumia.
He can’t pardon or commute illegal immigrants because their breach is civil, not criminal, but he could grant widespread relief from civil proceedings (including pre-removal detention) which a subsequent President might have difficulty reinstituting, practically or otherwise.
A raft of recess appointments to fill vacancies in the federal courts are certainly a possibility, but the damage potential is limited simply because few credible candidates would take so poisoned a seat. (Two or three strong candidates from states with two Democrat Senators is more likely, since they’d have a good chance at renomination by Romney in the typical distribution of judicial spoils.)
“The President has no pardon or commutation power over state convicts such as Mumia.”
Well, I did not know that. Thanks for straightening me out.