I've been thinking about independents and it hit me that they may not be the "swing voter". Socialists haven't registered as Democrats, or libertarians as Republicans. So his support could just be coming from people who've always been left of the democartic party, and are put in the same "independents" bin as those to the right of Ron Paul.
Conventional wisdom dictates that you need a decent showing with "independent" voters to win, and she isn't getting that.
BUT Obama won 2012 with a purely energise-the-base campaign, and lost among independents in every swing state (bar, ironically, NC).
So, (quick, ill-thought) moral of the story? Democrats have a large enough base to win the election, if they just turn up. Republicans need independents.
The situation seems to be reversed in midterms when the Dem base doesn't bother, the R base does, and they now have more control of state legislatures, governerships, Congress, the Senate, and a pure right-wing agenda, and are implementing it as much as they can, while Obama can't get a single thing passed.