The first problem that comes to mind with Eric Holder's nomination as Attorney General is his approval of the Marc Rich pardon.
You can see exactly how it happened: Bill Clinton dropped it on his desk on the final day of his administration. There wasn't time to research the negatives/he didn't take the time to read it carefully. It's really not a big deal in itself. But it puts "Bill Clinton's presidential pardon" on center stage when nothing should take the spotlight off the Bush administration's final pardons.
As for presidential pardons, there is some disagreement as to whether a president can pardon himself. English common law rules it out. The Constitution springs in large part from common law. In its only reference to pardons, the Constitution grants that the president "shall have Power to Grant Reprieves and Pardons for Offenses against the United States except in Cases of Impeachment." Congress can't prevent pardons, but the Supreme Court can step in and either nullify a pardon or support it.
A president could pardon himself but, some believe, a subsequent impeachment by Congress could overturn that pardon. There are probably several million shadings of opinion on this as on all Constitutional interpretations. But in politics, perception is everything.
I think Obama might have done better with an AG nominee whose record didn't contain a collision with an indefensible presidential pardon at a time. After all, George Bush may be weeks away from issuing a blanket pardon for his colleagues in an administration believed to be the worst and most lawless in American history. That's what we should be paying attention to, not trudging through yet another review of Bill Clinton's poor judgment.