Greenberg focuses on what he sees as technical failings of the campaign itself:
The Trump presidency concentrates the mind on the malpractice that helped put him in office. For me, the most glaring examples include the Clinton campaign’s over-dependence on technical analytics; its failure to run campaigns to win the battleground states; the decision to focus on the rainbow base and identity politics at the expense of the working class; and the failure to address the candidate’s growing “trust problem” or to learn from events and reposition.
Greenberg's account seems to rely on the conventional understanding of "white working class" that has started to drive me up the wall, i.e., white people without a four-year college degree. Even carving out "white working class" as distinct target group is problematic. The academic word "intersectionality" has been creeping into the general political vocabulary recently, a concept which looks at the effects of the overlapping of socially significant identities. "White" and "working class" would be an example of the intersection of particular race and class identities. I just wish that such intersections were discussed in a more nuanced way in political analysis and commentary. In that example, a more meaningful treatment would need to come up with a more sociologically significant understanding of working class, e.g., people who are (or should be) eligible to join a union.
The current polemical posture of corporate Democratic moderates in intra-party disputes with progressives is to treat any kind of emphasis on focusing on class issues and emphasizing advocacy of working-class issues as being opposed to civil rights and feminist goals. That keeps the waters on such discussions muddled. Not least because of a real history of American left groups playing off one such set of issues by pandering to the conservative side on others. For instance, advocates for female suffrage sometimes argued that it would provide a more reliable block of votes to preserve white dominance or protection against immigrants. Labor unions have often not treated racial and gender discrimination seriously enough, or even taken conservative positions on them. Such examples are not hard to find in American history.
But I'm particularly impressed with Greenberg's evaluation of the complacency aspect of Hillary's campaign. One big part of it was relying on a kind of demographic determinism:
Clinton and the campaign acted as if “demographics is destiny” and a “rainbow coalition” was bound to govern. Yes, there is a growing “Rising American Electorate,” but as Page Gardner and I wrote at the outset of this election, you must give people a compelling reason to vote. I have demonstrated for my entire career that a candidate must target white working-class voters, too.
Not surprisingly, Clinton took her biggest hit in Michigan, where she failed to campaign in Macomb County, the archetypal white working-class county. That was the opposite of her husband’s approach. Bill Clinton visibly campaigned in Macomb, the black community in Detroit, and elsewhere.
The fatal conclusion the Clinton team made after the Michigan primary debacle was that she could not win white working-class voters, and that the “rising electorate” would make up the difference.
He describes how Hillary's message was complicated in a big way by the Obama Administration's insistence on presenting their accomplishments in the best light. Instead of, say, emphasizing how many important things had been blocked by obstructionist Republican majorities:
Obama’s America was not a country in pain, but one where those left behind were looking for a seasoned leader to make progress. Obama and Clinton lived in a cosmopolitan and professional America that wasn’t very angry about the state of the country, even if many of the groups in the Clinton coalition were struggling and angry. Clinton decided only reluctantly to qualify that narrative in favor of one more sensitive to those who were left behind.Greenberg draws on contemporary polling data to argue that when Hillary did strike a Sanders-like position on economic issues, it drew a positive response from voters.
Obama’s refrain was severely out of touch with what was happening to most Americans and the working class more broadly. In our research, “ladders of opportunity” fell far short of what real people were looking for. Incomes sagged after the financial crisis, pensions lost value, and many lost their housing wealth, while people faced dramatically rising costs for things that mattered—health care, education, housing, and child care. People faced vanishing geographic, economic, and social mobility, as Edward Luce writes so forcefully. At the same time, billionaires spent massively to influence politicians and parked their money in the big cities whose dynamism drew in the best talent from the smaller towns and rural areas.
Clinton’s default position was Obama’s refrain about America ... [my emphasis]
Greenberg focuses on the horse race rather than the policy substance. So he doesn't really address how that complacent approach on the economy is also consistent with the corporate Democratic instinct that what is good for bank CEO's is good for America.