A politician might use every chance to emphasize that he/she was poor indeed to gain public sympathy and support. are they playing poor card? that doesn't sound idiomatic.
Aside from politics, when someone is trying to gain sympathy or support from the public by emphasizing that he/she is poor, like:
A thief was chasing by the police, but when he's cornered, he incited the crowd by___, claiming that he was poor and being unfair treated by the police, so the crowd was anger and he manage to get away with it.
In short, they are all using people's sympathy on poor and antipathy toward authority to arouse sympathy and get the best for themselves. Is there a idiomatic phrase/expression to describe this behavior?
edit: I make up some keyword to describe that behavior: hypocritical, using people' sympathy and antipathy, sneaky