Power Problems: The Small SIgns

I am not sure if power corrupts as much as it has a habit of revealing traits that were already there. 

The arrogant weasels whom I've known were weasels-in-waiting prior to gaining significant power. Some served apprenticeships in lesser positions where there was less opportunity for abuse and much of their time was spent sucking up to their superiors.

Always look for the small signs. See how they treat people who are unable to help their career. Look for any corners that are cut and for tendencies to hold grudges. Assess their ruthlessness but don't expect a consistent record of infractions.

Consider an extreme case: Stalin, in an early job as personnel director of the Soviet Communist Party, plugged his allies into positions while his charismatic rival Trotsky made speeches. Stalin was supposedly the soul of patience with any fool who wished to bend his ear, the man to talk to if you needed a favor, while Trotsky was too busy with loftier matters, rattling on about "permanent revolution." Far less eloquent, Stalin beavered away behind the scenes, gathering information, noticing slights, and nursing numerous grudges. Throughout this, he exuded an air of humility. He wore the mask of the reliable servant.

Stalin kept that mask as he eliminated competitors and continued the act after power was exclusively in his hands. General Secretary Stalin would deliver humble speeches before cheering delegates at Party Congresses but large portions of the audience were not around for the next Congress since he'd rewarded them and their families with either a bullet in the head or a stay in the gulag. 

One little hint they should have noticed: His Party name - Stalin - means "steel."