Essay about actors and performances on live stage

Write an essay about performances of actors on theater stage (and their affects on their audience). How actors can reflect horror? How they can reflect hope? Are there specific methods to reflect those emotions (horror and hope)?  Do not forget to mention the relation between actors on stage at the theatre and actors as politicians on a stage. What are the relation between those two? Also if possible refer to the effects of technology that changed last two decades on performing on stage. (Min. ref. 20)