Can jailbirds issue pardons?

From The Hill -

Trump says he would look ‘very, very seriously’ at pardons for Jan 6 defendants if reelected

Former President Trump said on Friday that he would look “very, very seriously” at pardoning those charged in connection with storming the Capitol on Jan. 6, 2021, if he ran for and became president again. 

Speaking during a Faith and Freedom event in Nashville, Tenn., Trump said the defendants charged in the Capitol riot were “having their lives totally destroyed and being treated worse than terrorists and murderers,” claiming that most had been “charged with parading through the Capitol.”

If one could, this one would probably just pardon himself, and only himself.

And fundraise off of both.

Of course, this could just be his attempt attempt at tampering with witnesses.