I always got the impression from her public persona that she thought she didn't need charisma, that she had "earned it", and that the power she had accrued over the years should be enough to deliver the victory to her.

Anecdotally, this is one reason Bernie did better than expected in the 2016 primaries.

I think it's possible to learn it, but a lot of charisma comes from empathy and focus on others. Awkward people can be very charismatic if they give the vibe they care about you. True selflessness isn't something most politicians are really known for..

And opportunity. She is married to charisma.