Your problem is that you are "calibrating" what you know Clinton
did, with what you
think Cheney has done. Even
if the final trier-of-fact finds a violation of one Act or another, the remedy will be for Cheney to turn over the documents. Hardly grounds for impeachment, and hardly grounds to argue that Cheney should have turned the documents over in the first place.
After all, Clinton was not impeached because he claimed "secret service" privilege (which was ultimately shot down), nor will Cheney find himself impeachable because he claimed executive privilege, as is his right.
"if the final trier-of-fact finds a violation of one Act or another" You're mixing up trier-of-fact -- which in some cases is a jury -- with a trier of law. There are no facts in dispute in this case. It's a pure question of law. But setting that aside, on your view Bush and Cheney should not be impeached if they comply with a court order to hand over the documents but should be impeached if they fail to refuse to comply?