Understanding of the psychology of tyranny is dominated by classic studies from the 1960s and 1970s: Milgram's research on obedience to authority and Zimbardo's Stanford Prison Experiment. Supporting popular notions of the banality of evil, this research has been taken to show that people conform passively and unthinkingly to both the instructions and the roles that authorities provide, however malevolent these may be. Recently, though, this consensus has been challenged by empirical work informed by social identity theorizing. This suggests that individuals' willingness to follow authorities is conditional on identification with the authority in question and an associated belief that the authority is right.
Haslam SA, Reicher SD (2012) Contesting the “Nature” Of Conformity: What Milgram and Zimbardo's Studies Really Show. PLoS Biol 10(11): e1001426. http://dx.doi.org/10.1371/journal.pbio.1001426