I rather see Cheney hang, but...

[zipplewrath]

3. Best damn idea ever

It is possible to issue pardons, where the person pardoned must do certain things prior to receiving them. Restitution is an example. He could issue pardons to Cheney, but they can only be exercised if Cheney does some things, such as admission of guilt, or providing testimony and cooperating with prosecutors.

Best of both worlds. He labels what they did a crime. And they'll never actually admit guilt, so they won't be off any hooks. Even better, there's not thing one that Cheney, or Congress or the courts can do about it.