When this enchantment enters, you draw a card and each opponent discards a card.
Whenever you surveil, return this enchantment to its owner's hand.
An ability that triggers "whenever you surveil" triggers after you're done surveilling, even if you have fewer cards in your library than the number of cards you're instructed to surveil. It even triggers if you have no cards in your library.
Disinformation Campaign's last ability triggers only if it's on the battlefield. It won't return from your graveyard.