I thought this was a very interesting essay from Sheri Berman on the Social Europe site. While her essay is focused on Europe I think there are some very clear lessons here for the left in the United States.
"Rather than rising numbers of immigrants or increasingly negative attitudes towards them, what seems to contribute most to populism’s success is the centrality of immigration to political competition. During much of the postwar period, political competition in Europe pivoted primarily around economic issues, and so voters who had conservative social views (for example, many members of the working class) didn’t vote on the basis of them. Over recent decades, however, political competition has increasingly focused on social issues such as immigration and national identity, leading voters to be more likely to vote on that basis.
When concerns about immigration are at the forefront of debate—in political-science terms, when immigration’s salience is high—the populist right benefits. This is because in most European countries right-populist parties now ‘own’ this issue: they are most associated with it and their voters are united in their views about it (whereas the left’s voting constituency is divided between social conservatives and social progressives). That populists benefit when the salience of social issues such as immigration is high explains why they spend so much time trying to keep such issues at the forefront of debate: demonising immigrants, spreading ‘fake news‘ about them and so on....
Parties succeed when the issues on which they have an advantage are at the forefront of debate: populists do well when attention is focused on immigration, green parties do well when attention is focused on the environment and social-democratic parties do well when attention is focused on economic issues and, in particular, on the downsides of capitalism and unregulated markets—assuming they have something distinctive and attractive to offer on the economic front. (This has not been the case for many social-democratic parties for too long but many authors at Social Europe are trying to rectify that.)
What the Danish elections should remind us is that politics is largely a struggle over agenda-setting. Defeating populism requires removing the issues on which populism thrives from the forefront of debate. But for the social-democratic left to succeed, it must do more than neutralise the fears populists exploit. It must also focus attention on the myriad economic problems facing our societies—and convince voters it has the best solutions to them."
Food for thought.