"I Was A Big Supporter Of Waterboarding" Ctd

A reader writes:

I think your enthusiasm may have gotten the best of you here. Yes, waterboarding is a war crime.  Those who performed it can and should be prosecuted.  Likewise everybody up the chain of command (military or civilian) who authorized or ordered it, all the way to George W. Bush.  You can also make a solid case against the attorneys (e.g. Yoo) who provided the legal "justification" for it -- at least, if our actions after WW II are any guide.

But Cheney is a much harder problem.  Simply put, he was NOT in the chain of command. 

As Vice President, he had authority only over his own staff.  He had no authority to order or authorize any action by the military, the CIA (or any other branch of the Federal government).  So, to find him guilty of war crimes it would seem to be necessary to either prove that he somehow usurped the authority to give such orders, or that he was specifically delegated authority in that area by the President.

Just arguing in favor of such actions is not enough.  It may be morally reprehensible.  It may be exceptionally stupid.  In my opinion, it was both.  But I don't see how you can make the leap from someone arguing for an action which he has no authority to implement to committing a war crime.  I confess, I regret it deeply -- but I just don't see the legal justification for it.

Or am I missing something really obvious?