Which working class?

I am going to have a post on a column by Ross Douthat about the possibility of "a real center-right majority" based on the working class.  However, it's a little complicated, so here's some background.

Just before the 2010 election, Barack Obama's approval rating had fallen to about 45%, only a little higher than Donald Trump's was just before the 2018 election.  Obama's rating was higher among college graduates (48%) than among non-graduates (44%).  But it was also higher among people with low incomes than among people with high incomes (50% among people who got less than $2,000 a month, 45% among 2-5,000, 45% among 5,000-7,500, and 42% among over 7,500).   Donald Trump got higher approval among people without college degrees (45% vs. 38% among college graduates), but also among people with higher incomes (31%, 40%, 50%, 48% for the income categories given above).

So who was more popular with the "working class"?   It depends on how you define it.  (Most sociologists would prefer to define class by some combination of occupation and self-employed vs. works for others, but few surveys ask those questions now).  Or you could bypass the question of defining the working class and just say that Trump is more popular among people with high incomes and low education, and Obama was the other way round.

For Obama, the gap between rating among more and less educated people grew over the course of his presidency:  when he started it was only a couple of percent, and when he ended it was 64% to 57%.  The income gap may have a little.  For Trump, the education gap has stayed about the same, and the income gap may have grown.   But in both cases, they were pretty stable--Obama's approval rating rose and fell, but when it did, it was by about the same amount among all groups.  (Trump's approval rating has been very steady among all groups). 

[Data from the Gallup Presidential Job Approval Center]