Were Bernie Sanders's primary voters really that socially progressive?

Question

In Bernie Sanders's campaign for president, he focused on economic issues. One thing that I found strange following his style of campaigning is that he seemed to try to reach out to social conservatives in a way.

What I mean is that his campaign focused on the working class, which seems to be a euphemism for individuals without college education or also lower-income individuals. People who are in "the working class" tend to be more conservative than educated people in many countries including the United States.

In 2016, the "working class" strategy Sanders employed seemed successful. He got big wins in the primary against Clinton (and Biden to an extent in 2020) in working class areas that Trump did better than Romney in 2016 or even 2020 (in Mexican-American areas such as South Texas).

This begs the question of if Bernie's supporters included more social conservatives and Trump voters, especially Obama-Trump voters. It is not implausible that some social conservatives were put off by his left-wing base and talking points but were pleased by his economic stances; and on the other side many college educated social liberals felt that Sanders' ideas were impractical or wasn't loyal enough to the Democratic Party but liked his talking points. It's not implausible given that ideology doesn't usually function on one dimension.

1: Were Bernie Sanders's supporters more likely to identify as conservative than Democratic presidential primary voters overall in 2016 and 2020? 2: Were there a disproportionate number of Sanders-Trump voters compared to Clinton-Trump voters and other recent presidential primaries?

Answer 1

1: Were Bernie Sanders's supporters more likely to identify as conservative than Democratic presidential primary voters overall in 2016 and 2020?

It seems the answer to this question is yes, at least among those who ended up voting for Trump in the general election:

https://twitter.com/b_schaffner/status/900376673270583296

Also see the "What kinds of Sanders voters supported Trump?" section in this article:

https://www.washingtonpost.com/news/monkey-cage/wp/2017/08/24/did-enough-bernie-sanders-supporters-vote-for-trump-to-cost-clinton-the-election/

2: Were there a disproportionate number of Sanders-Trump voters compared to Clinton-Trump voters [than in] other recent presidential primaries?

Assuming I understand your question correctly (see my comment and the slight annotation), the answer to this question is more mixed. First, the percentage of how many Bernie/Trump voters there were seems to be a little disputed but most agree it's somewhere between 6 and 12%...

• https://www.npr.org/2017/08/24/545812242/1-in-10-sanders-primary-voters-ended-up-supporting-trump-survey-finds
• https://en.wikipedia.org/wiki/Sanders%E2%80%93Trump_voters
• https://www.washingtonpost.com/news/monkey-cage/wp/2017/08/24/did-enough-bernie-sanders-supporters-vote-for-trump-to-cost-clinton-the-election/

Now see the "How does this compare to other elections?" section in the final article. Here are some key quotes:

So let’s compare the Democratic primary with the Republican primary. In the VOTER Survey, only 3 percent of those supporting Texas Sen. Ted Cruz reported voting for Hillary Clinton, as did 10 percent of Florida Sen. Marco Rubio’s supporters and 32 percent of Ohio Gov. John Kasich’s supporters. So Sanders supporters were about as likely to vote for Trump as Rubio’s supporters were to vote for Clinton, and far less likely than Kasich supporters were to vote for Clinton.

Another useful comparison is to 2008, when the question was whether Clinton supporters would vote for Barack Obama or John McCain (R-Ariz.) Based on data from the 2008 Cooperative Campaign Analysis Project, a YouGov survey that also interviewed respondents multiple times during the campaign, 24 percent of people who supported Clinton in the primary as of March 2008 then reported voting for McCain in the general election.

Thus, the 6 percent or 12 percent of Sanders supporters who may have supported Trump does not look especially large in comparison with these other examples.