Card-stacking propaganda is when only one side of an issue is showcased, and the other side is not mentioned or played down. It is frequently used in advertising, such as when commercials for a product only show positive testimonials, giving the impression that every consumer likes the product.
Card-stacking propaganda is also often used in politics, when one candidate presents only his side of the argument to discredit the opposing candidate. "Card stacking" comes from the phrase "stacking the deck," referring to when a person sets up a deck of cards in a favorable order. Magicians stack decks before performing card tricks, and gamblers stack decks when cheating at card games.