Where in the Constitution does it say that pardons and commutations are supposed to go through a process?
Sure, that's the precedent, and I'm not saying they shouldn't be subjected to a review process, but strictly speaking, where is it mandated?
Also, it's an incredible over-reaction imo, to say this is "the single greatest act of corruption in American history." Even with the impact you believe it would have on our judicial system, that's ignoring an awful lot of US history. Besides, Stone wasn't pardoned; he's still a convicted felon, and rightly so,as Mueller pointed out.