A few days ago Bernie Sanders called out the Democratic Party.

"The evidence is pretty clear," Sanders continued, "that when you lose the White House in a campaign against a gentleman, who, I believe, will enter the White House as the least popular candidate in the history of this country, when you lose the Senate, when you lose the House, when you lose two-thirds of state governor's chairs, when you've lost some 900 seats of legislatures around the country in the last eight year, I think it is time for the Democratic Party to reassess what it stands for and where it wants to go."
Sanders said that amounted to a choice for Democrats to decide whether they're standing with "corporate America" and Wall Street or with a declining middle class

So what do the Dems stand for?
From the 1930's to the 1960's the Dems stood primarily for economic progress and equality for the working class, and it was a winning strategy. Some will claim the Dems still stand for that, but the working class increasingly does not believe it.

Part of what drove the Trump takeover of 2016 was the fact that liberal culture is obsessed with identity politics based on race and sex, having all but forgotten anyone who isn’t a racial, ethnic, or sexual minority — and the bread-and-butter issues that exist outside of those categories. Classism is a very real thing too — and this year, the white working class of America stood up and said very loudly: You’ve forgotten about us.

Anyone that has spent any time on liberal blogs has notice the priority of social issues over economic ones, even to the point of accusations that prioritizing the economy is a symptom of white privilege.
The problem with de-emphasizing the economy is that the Dems aren't speaking to the concerns of the voters.

A majority (52 percent) of voters said the economy was the most important issue facing the country. (Voters were given a choice of four issues; “terrorism” was the second most commonly named “important” issue, with 18 percent choosing it.)

Social Justice Warriors will most likely view the exit polls as evidence of the pervasive white privilege in American society. But the reality is that the exit polls show the opposite.

Overall, 46% of Hispanics cited the economy as the most important issue facing the country, followed by terrorism (20%), immigration (19%) and foreign policy (11%).

Unless liberals are going to start accusing Hispanics of White Privilege, the obvious conclusion is that liberals aren't just out of touch with the white working class, liberals are out of touch with minority working class as well.

When you think about it, this shouldn't be a big surprise. People of all races are pretty much alike, and have similar concerns. The trap of identity politics leads liberals to forget that basic fact.

Besides being for the working class, liberals used to be noted for being against unnecessary war.
After 15 years of expensive, inconclusive, non-stop war, the American public is war weary.

Yet, where is the anti-war left?

Just days after Donald Trump’s upset victory in the 2016 presidential election, Sanders published a high-profile article in the New York Times outlining the policy agenda for progressives going forward.  The piece contained the usual laundry list of identity politics and spending proposals that left-wing types have been pushing for decades.  What was striking, though, is that the article contained not a single word—not a single word—about foreign policy.  The United States is mired in the longest war in its history in Afghanistan, it has returned to the scene of its last major interventionist disaster in Iraq, and it is already entangled to a dangerous degree in Syria.

If Bernie can't be bothered with a destructive failure of a generation-long war, what does that say about liberals in general?

“What anti-war movement?” former Congressman Dennis Kucinich asked when called for comment last week. Medea Benjamin of the radical group Code Pink agreed: “the antiwar movement is a shadow of its former self under the Bush years.” Cindy Sheehan quipped that “The ‘anti-war left’ was used by the Democratic Party. I like to call it the ‘anti-Republican War’ movement.”

The demise of the anti-war left isn't something new - it started declining in 2003 - but the total abandonment of the issue by liberals, like the de-emphasizing of economic issues, leaves Democrats will precious few ways to connect with a majority of voters.
It also leaves the Dems with the fundamental problem of describing what the party actually stands for, outside of identity politics.