charisma is a great quality to have - imo it is to do with exuding warmth, empathy and purpose even when everyone has fallen by the wayside. I think the magnetic quality is very real and does generate devotion and love rather than making people follow blindly.
In the film industry charisma may have to do with how a person comes across on screen - in this sense even Marlene Dietrich could be said to be charismatic despite being cold and unfriendly in real life. So I guess in her acting ability she could portray something quite different from what she was in real life.
but getting back to real life - I think Bill Clinton had great charisma and so did our very own Tony Blair. Probably Margaret Thatcher too.