http://www.linguee.com/english-german/search?source=auto&query=play+the+card You can use this expression creatively to describe any situation when you want to obtain a tactical advantage by relying on something which the other person will find it hard to oppose See the examples at the link. (ignore the ones referring to card games!) Good question.

I've just seen this expression used in a review of a film about a woman diagnosed with Alzheimer's disease. Her husband was angry with her about failing to attend a dinner party, and she 'played the illness card', even though we suspect that she deliberately missed it.