She's all-in on Iowa. If she doesn't make top 3 in Iowa, and then if she has a disastrous showing in New Hampshire (which the polls indicate now, despite her being from a neighboring state), then her already weak fundraising will go off a cliff.

It's also feeling like Kirsten Gillibrand (who I generally like) is having more trouble catching on than can be sustainable for the long haul.

Beto might quietly drop out and hope nobody notices if he can't come in top-5 in some of the early states. Possibly Castro as well, but I think he's running for VP, so he wants to do as many debates as he can even if he isn't winning states.