You can use the transmogrifier to copy the deck from one of your campaigns to another of your campaigns A listing of all the objects in the game that are eligible to be moved will appear. Just drag and drop between the two lists to copy elements between the games. Note that you are copying elements, not moving them, so the original will remain in the first game. If you look close you will see the word deck faintly under the ADD to Campaign. I doubled checked in a test board and it does let you transmogrify decks between your campaigns.
