moral compass
noun /ˌmɒrəl ˈkʌmpəs/
  /ˌmɔːrəl ˈkʌmpəs/
- the ability to judge what is right and wrong and to behave in an appropriate way道德指南针:判断对与错并以适当方式行事的能力 - He is not the only politician who has lost his moral compass.他不是唯一一个失去道德指南针的政治家。 
 
- He is not the only politician who has lost his moral compass.