As Democrats and other center-left parties struggle to understand why working-class voters have turned against them, they reach readily for economic explanations. Yet most flinch from confronting another potent driver of blue-collar anger — uncontrolled immigration. Of course, that’s partly an economic issue too. But it also illuminates the deep rift between elite and popular opinion on emotive questions of national sovereignty, cultural identity and democratic agency in deciding who can enter one’s country and become a citizen.

Stopping illegal immigration has been President Trump’s most reliable rallying cry. His call to wall America off from a flood of “criminal aliens” in 2016 helped him forge a strong bond with non-college voters. He went back to the immigration well in his 2024 comeback, when those voters again ranked the issue as a top concern, second only to high living costs. Hostility to mass migration also is the rocket fuel propelling neo-nationalist populists in Europe.

These include the far-right Alternative for Germany party, which recently made startling gains in state elections; France’s National Rally, now leading polls ahead of next year’s presidential election, and the United Kingdom’s fast-rising Reform Party. Across the West, working-class voters feel betrayed by political elites who lecture them about the aggregate economic benefits of more immigration and belittle their doubts as nativist if not racist.

Despite the issue’s enduring salience, few center-left parties have figured out how to defuse it. Denmark is a conspicuous exception. Since the Social Democrats came to power in 2019, they have slowed the pace of immigration while speeding up deportation of uninvited gate crashers. They have also moved aggressively to integrate migrants into Danish society, passing “parallel society” laws to prevent their concentration in segregated communities. European progressives have decried the shift as a concession to right-wing xenophobia.

But Mette Frederiksen, who won her third term as prime minister last June, maintains that a restrictive migration policy is integral to her party’s historic commitment to social solidarity. “Being a traditional Social Democratic thinker means you cannot allow everyone who wants to join your society to come,” she told the New York Times. With porous borders, “it’s impossible to have a sustainable society, especially if you are a welfare society, as we are.”

Fredericksen believes admitting fewer migrants and speeding their assimilation into Danish life are key to sustaining public support for the high taxes necessary to support Denmark’s generous welfare state, which corrects for economic inequality. That approach has enabled her party to stem working class defections while marginalizing the hard-right Danish Peoples’ Party. She also emphasizes a critical point that seems to elude many on the U.S. and European left: The economic and social costs of large-scale immigration — competition for jobs and downward pressure on blue collar wages, gang-related violence, strains on schools, housing, public health and other services — are not distributed evenly.

They fall more heavily on wage earners than highly educated and well-heeled Danes. Center-left governments in other Scandinavian countries are following Denmark’s lead. Prime Minister Jonas Gahr Store’s “Plan for Norway” includes calls for “clearer and stricter” immigration laws that tighten rules around family unification, speed up deportation of immigrants who don’t qualify for asylum and combat criminal gangs that help people enter the country illegally. Sweden’s Social Democrats, historically a working-class party, also have executed a U-turn on immigration.

“We had one of the most generous asylum systems in Europe, and that was wrong,” admits the party leader Magdalena Andersson, who is working to form a center-left governing coalition.

Democrats, who have long admired the Nordic economic model, should learn from the new Nordic model on immigration. It offers a humane path to curbing illegal migration in contrast to the cruel and violent tactics of Trump and his sadistic henchman Stephen Miller. The party, however, has yet to reckon with the Biden-Harris administration’s immigration debacle. Biden loosened asylum and parole rules and until 2024 made little effort to secure the border. Migrants saw the green light and surged across it in record numbers.

Voters won’t trust Democrats to enforce immigration laws until they break emphatically with progressive demands for “decriminalization” and open borders. They should recall that Presidents Barack Obama and Bill Clinton kept illegal immigration under control despite taking flak from the left and immigrant rights’ groups for robust deportation programs. Democrats are keenly attuned to how economic and technological change have undermined working Americans’ prospects for upward mobility. The same forces have sparked the mass migrations of the 21st century — and a furious popular backlash.

To keep faith with their traditional working-class constituents, center-left parties need to show they can control borders, restrict illegal entry and assimilate newcomers in ways consistent with liberal and social democratic principles. The Nordic Model shows that’s not a mission impossible. Will Marshall is founder and president of Progressive Policy Institute.