From Politifact:
“Ford’s pardon ended any possibility of Nixon being prosecuted criminally. It covered more than obstruction of justice, however. It excused Nixon for “all offenses against the United States which he, Richard Nixon, has committed or may have committed or taken part in” during the period from January 20, 1969, through August 9, 1974. In short, Ford’s pardon covered any crimes Nixon may have committed between the time he was sworn in for his first term and the day he resigned.”
https://www.factcheck.org/2008/06/blanket-pardons/
However:
“Under the Constitution, the president has the power to grant “reprieves and pardons” for federal (but not state) crimes, essentially wiping out a person’s convictions. The power is, as Trump says, “absolute” in that pardons can’t be overturned by Congress or the courts.”
https://apnews.com/article/e068fa97caaa4a8eaee351eb380dd72b
There may be hope yet. If I’m understanding this correctly, in order for Pence to blanket pardon, he must specify the dates covered. If he covers a timeline before the Presidency, red flags galore would no doubt signal the deathknell of the current incarnation of the GOP.
It also doesn’t preclude the AG of NY or Michigan or Oregon, etc., etc. from going after Trump.
I admit I may be completely butchering this with wishful thinking, but I won’t apologize for dreaming.