Most of the 2016 USA election results were pretty typical

In Why did the 2016 election look so much like the 2012 election? Ezra Klein reports on work shoing that most voters in the USA vote according to partisan identity, not policies or candidates.

A few months ago, I stopped by Larry Bartels’s office at Vanderbilt University. Bartels, alongside Christopher Achen, is the author of Democracy for Realists, which I’d become a bit obsessed with. The book argues that decades of social science evidence has shattered the idealistic case made for how voters in democracies act, and the reality is that “even the most informed voters typically make choices not on the basis of policy preferences or ideology, but on the basis of who they are — their social identities.”
I sat down with Bartels shortly after the 2016 election, and I had a dozen ideas for how his book helped explain the unusual results. But he wasn’t buying my premise. To him, the election looked pretty typical.
The Democratic candidate won 89 percent of Democratic voters, and the Republican candidate won 90 percent of Republican voters. The Democrat won minorities, women, and the young; the Republican won whites, men, and the old. The Democrat won a few percentage points more of the two-party vote than the Republican, just as had happened four years before, and four years before that. If you had known nothing about the candidates or conditions in the 2016 election but had been asked to predict the results, these might well have been the results you’d predicted. So what was there to explain?