she didn't understand the constitutional role of her potential job. The links I've provided actually show her to be alot closer to correct >per that definition< than her critics.
Is that what she meant? Maybe, maybe not...all up to interpretation. I'm leaning towards it being a poor choice of words to translate the actual role of President of the Senate. Her debate answers showed she understood that role to be more limited but also showed a desire to perhaps become more involved in the more traditional role.
In essence, like stated elsewhere, its about context (very limited in this case) and a strong desire by the media to find anything and everything to go after with a vengeance.
If they would go over some of the things Biden has said in his history with the same level of furor, the world would probably think a lot less of him too.