In the states ahead, Clinton needs exactly what she didn't have in Iowa and New Hampshire: a clear winning argument against Sanders. Right now, though, she has four arguments, many of which are in tension with each other:
All four of these arguments have some merit, but there's no particular reason to think that any of them are naturally more appealing in the big March states or to minority voters than they were to white voters in the early states. If she's able to get more persuasive on point 4, and do a better job of clarifying which of 1 through 3 she actually wants to argue, then there's every reason to believe she'll win the nomination. But if she continues to muddle through buoyed by a vague sense of inevitable minority support, then she's in trouble.
- Clinton and Sanders largely agree on goals, but Clinton has a more realistic plan for achieving those goals.
- Sanders's left-wing policies on taxes, health care, and higher education are in facttoo left-wing and should be rejected in favor of more moderate ones.
- Sanders is not in fact as left-wing as he seems, as you can see from his stance on gun control and his votes on the 2007 immigration reform bill.
- Whether or not you prefer Sanders on the merits, you should vote Clinton, because Sanders is easier for the Republicans to beat.
I'll throw in a fifth reason: turnout compared to 2008. It's down big time for the Democrats in both Iowa and New Hampshire so far. The argument that Bernie and Hillary have to work to earn votes makes much more sense when you realize that turnout is worse than 8 years ago, and significantly so.
Let's hope that happens.