metaphor in political situations relates to the risk of “political suicide” that a person would face by raising certain taboo subjects or having points of view that are either censored, shunned or considered highly controversial or offensive to advocate or even mention. - https://en.wikipedia.org/wiki/Third_rail_(politics)
Malala touched “third rail” as a little girl
“I couldn’t understand what the Taliban were trying to do. “They are abusing our religion,” I said in interviews. “How will you accept Islam if I put a gun to your head and say Islam is the true religion? If they want every person in the world to be Muslim, why don’t they show themselves to be good Muslims first?” ― Malala Yousafzai, I Am Malala: The Girl Who Stood Up for Education and Was Shot by the Taliban. October 8, 2013