hot button

Short definition from Wiktionary

Noun

1. 1
   A central issue, concern or characteristic, especially one that motivates people to make a choice; sometimes also one that people seek to delay taking sides on.
2. 2
   The principal desire that a salesman needs to "hit" in order to make a sale.
3. 3
   An emotional trigger; something that arouses strong emotion or opinions.
4. 4
   Alternative form of hot button.

Adjective

1. 1
   Alternative form of hot-button.
2. 2
   Arousing intense reactions; eliciting strong emotion or controversy.