What happens if Hillary Clinton stalls or stumbles?

At this point, with the Republicans in chaos and Bernie Sanders' insurgency her only significant Democratic opposition, Hillary Clinton should be dominating the polls. That she's not must be scaring the bejesus out of the Democratic establishment. But what are they going to do about it? It's not like they have a deep bench. They don't want Elizabeth Warren or Sanders, though either of them would be electoral gold in November. Joe Biden is older than dirt and goofier than a Shmoo. Andrew Cuomo gives cynicism a bad name and has not been seasoned by a previous national run. The idea of drafting Al Gore is fantastical, as is the thought that they'd find Jim Webb or Martin O'Malley fit to run (who's Lincoln Chafee, again?). That the party kingmakers should have seen this coming is beside the point. What are they going to about it now?

Here's the breakdown:
Bush leads Clinton 41-36 in Colorado; 42-36 in Iowa; and 42-39 in Virginia.
Walker leads Clinton 47-38 in Colorado; 45-37 in Iowa; and 43-40 in Virginia.
Rubio leads Clinton 46-38 in Colorado; 44-36 in Iowa; and 43-41 in Virginia.

These are all states Obama won both times and they are essential components of a Democratic victory next year. "Trustworthiness," or lack thereof, seems to be what's doing Clinton in, and there's little about her halting, content-less campaign so far to indicate she can overcome people's distrust and dislike. Instead of trying to protect Clinton in the primaries, the Democrats should designate a substitute now or face having her drag the rest of the party's congressional and state candidates down with her when she whiffs in November 2016.

The rest of the story: Hillary Clinton is trailing the 3 strongest Republican candidates in 3 key swing states by Brett LoGiurato (Business Insider).

Reading list: Why Liberals Have to Be Radicals by Robert Kuttner: The reforms needed to restore the country's shared prosperity are to the left of all the candidates, including Sanders.

Addendum: I am asked what I have against former Senator Jim Webb. I don't have any particular issues with Webb that I don't have with any likely Democratic nominee; but I think the party poohbahs would regard him as a minor candidate, too independent, too unseasoned, too Southern, too identified with the military to please the party base, and probably a little too difficult to brand plausibly as a progressive (despite the fact that he voted with the party most of the time that he was in the Senate), something any Democratic Party nominee will have to pretend to be in 2016.