Anyway, Carter's advice would be the best advice for her if she wanted to help her party. I don't think he want's her to become president, and she souldn't be, unless of course she were to be the democratic candidate.
Sadly, it's a bit late for her to join, and with only two supporters (one of them Canadian), she wouldn't get far. Don't underestimate our ability to influence things. Just look at Obama in Ohio. Without our interference the Dem race could have been officially over by now.