Obedience to Authority

When looking at Milgram's Obedience to Authority, one can see how this serves as an explanation for the terrible regimes throughout time.  It is hard to believe that Hitler, Stalin, Mao, and Mussolini would have came to power if it were not for this principle.  These regimes rested upon the sole ability that the people would not think for themselves and listen to their own morals.  The question I pose: since all of these leaders came up as trusting leaders who would bring real change, what kind of test should we use today to test the intentions of our own political leaders.