It's not so limited in scope, Congress could pardon half the felonies in the law book. It's only limited because Congress does yet have the authority to pardon people already in bars (or does it? I could be wrong here), but that could be changed.
As for Nixon, not pardoning him would have led to some very messy politics (does he even quit?) in the middle of the oil crisis/price controls/etc. I have no idea how it would have played out, but the US needed at the time a functioning presidency (more than usual).
As for Nixon, not pardoning him would have led to some very messy politics (does he even quit?) in the middle of the oil crisis/price controls/etc. I have no idea how it would have played out, but the US needed at the time a functioning presidency (more than usual).