I've never necessarily thought that HAD to be the case. First, I thought, "she could run as the VP candidate and try to stay below the radar." Then bump off the head guy afterward, getting into power that way. Lately, I've thought, "she can simply choose or annoint the ticket, work to get them elected, then become veep from the senate, if the ticket wins. Then she could conspire to move up from there, without even being elected." It's not that far-fetched, given that this has happened before.
I just don't see her winning or even placing herself in the limelight in order to win. It's just not her style. She's a backdoor vermin.