An article in Vox today makes a compelling case that, while the Presidential race may look good and the House Republicans are in disorder, Democrats, and the Democratic Party, are actually in trouble at this point. And it's all about the non-Presidential races.
Sure, the Presidency is important, but:
there are also thousands of critically important offices all the way down the ballot. And the vast majority — 70 percent of state legislatures, more than 60 percent of governors, 55 percent of attorneys general and secretaries of state — are in Republicans hands. And, of course, Republicans control both chambers of Congress.
If all politics is local, there are few localities where Democrats have control - or effective representation.
The article tries to make a case that Democrats are currently too liberal. I disagree there; the rise of Sanders indicates a groundswell of interest in liberal positions, and even Clinton has drifted left on a number of issues in response. However, the article is correct in that:
Democrats are currently engaged in a slightly bizarre bidding war between Hillary Clinton and Bernie Sanders to see whether Congress in 2017 will reject a legislative agenda that is somewhat to the left of Obama's or drastically to its left.
And this is being done with (apparently) no thought to Congressional or state-level races. (That's true even on this site - I see plenty about Sanders and Clinton, and hardly anything about state-level races.)
Is 2016 going to be a wave election for Democrats? Not likely. Wave elections usually ride the coattails of dissatisfaction with a current President, and the current President is (according to reliable sources) Democratic. The best bet is a wave against the Republican Congress, but that's pretty unlikely to happen, particularly with current Democratic leadership (looking at you, Debbie Wassermann-Schultz).
So what can be done? At this point, it's going to take a lot of local-level work. Democrats, and Democratic Parties, up and down the ticket have to (1) start aggressively marketing Democratic ideas and ideals, and (2) focus on winning elections - every election.
Sanders vs. Clinton is interesting. But the real war is being - or should be - waged elsewhere.