Maybe I am misconstruing your argument? Is your argument that if Trump pardons himself, he should be impeached then?
No -- absolutely not. The proper remedy for an invalid pardon would simply be voiding the pardon, not impeachment. To me, that would be...silly. You would impeach him for the underlying offense that you think he committed -- not for him pardoning himself for that crime.
My point is that the ultimate limitation on a President's power is the power of Congress to impeach, convict, and remove from office. This argument over whether or not a President has the legal authority to pardon himself has no bearing on that. It's irrelevant to any substantive debate -- it's relevant only to the legal maneuverings with Mueller.
Also, it is important to note that a sitting President likely cannot be indicted anyway -- Mueller himself already has stated that he doesn't have the power to indict Trump. You'd have to remove him from office first via impeachment,
then prosecute him. And as I stated above, nothing about the pardon power impacts impeachment.
Would you be ok if Obama pardoned himself? or said this?
Well, what I would upset about if he would have committed a criminal act, not him trying to pardon himself for it. And I wouldn't care what he said about it -- whether or not such a pardon would be effective ultimately would be up to the Supreme Court. Either he has the power, or he doesn't. I personally don't think the Supreme Court would uphold a pardon that was issued by a sitting President, subsequently impeached, that would apply to crimes for which he wasn't even charged until after he was already removed from office. But if it
was a valid exercise of Presidential power under the Constitution, then the pardon would be valid. The problem would be poorly-drafted Constitutional provision that should be fixed.
So again...I think this is much ado about nothing. It's just another thing about which some people are going to get their panties in a twist, that ultimately is completely irrelevant.