These are different times since 1974. The political fallout from a pardon of Trump would be much greater than there was for the pardon of Nixon. We were a different Nation then; less partisan, and less captive to the barrage of media and information.
I have always believed that Ford pardoned Nixon to avoid a massive trial of Nixon and massive Congressional investigations of Watergate without end. Ford rightly reckoned that the Democrats were going to make Nixon's trial (if it came to that) the biggest thing since Nuremberg, and THAT would hurt the party, long-term, worse than a pardon.
The Democrats are, right now, on course to a trifecta in 2020. A lot can happen, but I think the most likely outcome in 2020 as of this moment is that the Democrats control both houses of Congress by small margins and a Democrat is President. While I never doubt the Democrats' ability to snatch defeat from the jaws of victory, there is a limit of negative publicity that any party and any candidate can withstand, and Trump, the President, reflects on his party in Congress.
I will say this: What the Democrats should do in 2021, if they get this lucky, is NOT to pardon Trump, but NOT to bring new investigations. Let the Justice Department and regular Law Enforcement agencies investigate all of it. The Democrats should use such political positioning to pass their agenda before the GOP knows what hit them.
I agree with all of this.
