One of the themes that is very prominent in this US Presidential campaign is the relationship of the discouraging economic prospects many people perceive for themselves and the function of ethnic/religious/racial prejudice.
The mainstream pundits have a long-standing version of that relationship that goes back to the days of 1968 and George Wallace and Spiro Agnew, the early years of the Southern Strategy and the hardhats-vs.-antiwar protesters meme. That script says that salt-of-the-earth workin' folks have all kinds of backward prejudices and they are easy prey to rightwing demogaguery on race and gender. The usual implication of this is that the Democrats have to be understanding about this and need to pander to racial and other prejudices themselves in response. Bill Clinton's "Sister Soljah moment" oin 1992 is the pundits favorite prototype of this approach. Tom Edsall has been peddling this outlook for at least 25 years now.
The other approach is to stress the potential for solidarity around economic issues to outweigh the anti-black, anti-Latino, anti-immigrant sentiments, often with the assumption that the problems of racism and xenophobia are a result of social conditions and particularly economic ones.
The first view tends to the result of progressive/liberal politicians and leaders downplaying anti-racist or pro-immigrant advocacy, or even to embrace it. The second approach allows room for explicit anti-racism and pro-immigrant positions, but in practice politicians often use it to avoid talking about divisive issue of race and nationalism.
For someone with any kind of progressive/left view, it's necessary to take full account of both racism and other forms of bigotry as such, and to be very aware of how bad economic conditions may influence them.
But the Democratic primary has produced something of a polarization within the Democratic Party on this issue. The center-left neoliberalism with which Bill and Hillary Clinton have long identified is supportive of a left position on matters currently thought of as "identity" issues (women's rights, LGBTQ issues, anti-racism, pro-immigrant) while leaning very heavily toward corporate positions on regulation, trade, taxes and privatization.
Bernie Sanders' positions on those issues are, if anything, more supportive of such left "identity" issues than Clinton, though obviously the prospect of becoming the first female President of the US means that she literally embodies the women's-rights position in a way that Bernie can't. But he represents a New Deal social and economic posture that is distinctly different from the cautious Wall Street-friendly neoliberalism of Hillary Clinton.
And the binary Hillary-Sanders has influenced the way in which the relationship between economic conditions and social bigotry.
Ed Kilgore scoffs at the emphasis on economic conditions, "Sorry, but I don't think uncontrollable rage at having to 'press 1 for English' or say 'Happy Holidays' can be explained by displaced anger over wage stagnation or the decline of the American manufacturing sector." (The Meaning of Trump’s Cult of Political Incorrectness New York 07/05/2016)
He makes an excellent point. At least so far as what he's rejecting is the lazy pundit version of the story. There are lots of white people who really don't like black people. Or Latinos. There are xenophobic people who really hate foreigners and immigrants. The psychological conditions behind that are varied and complex. But they clearly don't result directly from people being in poor economic situations. Because rich bigots are scarcely unknown.
Adele Stan in The Trump Campaign: Bigotry With a Purpose The American Prospect 07/06/2016 gives some of the sobering poll findings on the strength of racist, religious and xenophobic prejudices in the US currently.
There is some non-trivial number of white voters who in practice prefer the satisfaction of being in the White Man's tribe against Those People to economic policies that would clearly benefit themselves and people in similar situations. But they exist and vote along a continuum that goes all the way from white supremacy to anti-capitalism.
And that's looking at the range of political preferences in terms of the left-right dimension, which is indispensable in thinking about politics and elections. But the complex of political opinions and preferences live intertwined with each other. The left-right continuum cuts across gender and family lines, across classes and religions, across racial and regional lines. The issue of public funds for private schools in the 1950s and 1960s was primarily debated in terms of Catholic-Protestant differences and church-state concerns. And the way they do so changes over time. Conservative Protestants in the South tended to oppose it, because it was seen as a "Catholic" issue. But in the 1970s, private "segregation academies" sprang up all over the South to avoid the integration of public schools. And since then, conservative white Protestants in the South have been far more supportive of various forms of public funding for private schools.
And people not only have political opinions, they have political priorities. Someone who concentrates her political attention, activism and donations on fighting for abortion rights is making that issue her priority. That doesn't mean that she's opposed to affirmative action and anti-discrimination laws, or that she opposes a $15 minimum wage. It also doesn't mean that she supports them.
To take the racism/economic-conditions question as a binary for a moment, there is no simple causal relationship between a person perceiving (rightly or not) that their personal economic opportunities are restricted and that person embracing white racism. White racism has to be confronted for what it is.
But facing restricted opportunities or being threatened with poverty or drastic drops in income can make people look to politics for something that provides a change. And if they don't hear politicians addressing the economic issues in a meaningful way, they are likely to be open to demagogic racial appeals. In some cases, a racist politician can also offer economic policy that sound solid, and may actually be so. George Wallace did that to a significant extent in his political career in Alabama. In the 1960s, black voters in Alabama favored Wallace over the available alternatives at the time because he did state for some policies like free school textbooks that offered a comparative benefit. Even though he had opposed voting rights for African-Americans and supported segregation and racial discrimination.
But at the very least, moments of improving economic opportunities for whites provide more promising conditions for combating racism head-on. And it is possible to combine the two. As Jamelle Bouie noted in, Why Democrats Can’t Win Over White Working-Class Voters Slate 11/14/2014, "for a new rhetoric of populism to work ... it needs to come with a commitment to universal policies that working-class whites like and support. (It’s no coincidence that the most liberal working-class whites belong to private and public sector unions.)" (my emphasis)
This article links to several others looking at such issues in contemporary Europe: Brexit, Trump and the challenge of populism 07/06/2016. There is certainly a lot to be learned from their experience. But multiparty systems do present different constellations than the American two-party system does.