At a town hall in Oskaloosa, Iowa, last week, Sen. Bernie Sanders (I-VT) was questioned on the feasibility of open borders.

Sanders, who is again running for the Democratic presidential nomination, was quick to repudiate the policy. “If you open the borders, my god, there’s a lot of poverty in this world, and you’re going to have people from all over the world,” he said according to Politico. “And I don’t think that’s something that we can do at this point. Can’t do it.”

As a front-runner in a crowded 2020 field, Sanders has the opportunity to present a vision of justice and human dignity when it comes to immigration that helps bring the issue to the forefront of the primary. Time and time again, he has pushed the boundaries of political feasibility, popularizing socialist ideals that were previously disregarded as fringe demands, such as Medicare for All. Sanders inspired millions in the 2016 Democratic primary with an unapologetic stand against wealth inequities and for the people. It is essential that progressives challenge Sanders on his immigration stance.

While it is true that migrants are a net boon to the economy, focusing on their economic benefits misses the point altogether. We must welcome migrants not because they bolster our economy, but as a matter of basic human dignity.

Even so, open borders, an immigration policy allowing the free movement of people between nations, are not only the moral choice; they are well in line with Sanders’ commitment to the working class. Immigration is fundamentally a labor issue, and Sanders does himself and the progressive movement a disservice by paying heed to nativist talking points.

Conservatives argue that increased immigration displaces residents of the United States. As the supply of laborers expands, they claim, immigrants will take jobs at ever lower pay, depressing wages and raising the unemployment rate. But that argument misses a few key points. First, while an influx of immigrants means more people in the labor pool, it also means an increase in demand for goods and services that translate into more jobs. Where immigration enforcement does happen, local economies can suffer. Following the 2008 raid in Postville, Iowa—one of the largest worksite raids in U.S. history—businesses shuttered, houses stood vacant, and the economy collapsed. “It cratered the Northeast Iowa economy,” said Aaron Goldsmith, a local business owner, in an interview with Marketplace. “A lot of innocent people got really hurt.”

Second, employers pay immigrant workers less in large part due to the leverage they incur as a result of immigration status. Forcing undocumented workers into the shadows drives down wages for everyone by cementing their status as second-class citizens. By weaponizing the threat of deportation, employers enjoy access to a cheap labor force and threaten those who demand better into submission. The logic is circular: It is a migrant’s very status as “illegal” that forces them to accept low pay and miserable work conditions. Employers have been caught time and time again threatening to call U.S. Immigration and Customs Enforcement when workers demand back pay or basic worker protections. Without the threat of immigration enforcement, bosses would lose the very leverage that allows them to pay undocumented workers poverty wages.

Third, when employers do lower wages, it speaks less to migration itself rather than to corporate greed—something Sanders has never had trouble pushing back against. Corporate profits are at an all-time high, and it’s not immigrants pushing down wages, it’s record-breaking executive pay.

In repudiating open borders, Sanders fails to engage with not only decades of U.S. intervention—in Latin America alone, the United States supported right-wing death squads in Argentina, Honduras, Nicaragua, El Salvador, and Chile—but also with exploitative trade deals that force families on the migrant trail. Take NAFTA, a 1994 trade arrangement between the United States, Mexico, and Canada that promised more jobs and higher wages for workers on all sides of the border. It’s an issue Sanders himself spoke about this weekend.

In practice, NAFTA was never about workers, but about the consolidation of class power: The rich got richer and the poor bore the brunt, whatever side of the border they inhabited. Though workers in the United States suffered job losses and depressed wages, Mexican workers arguably suffered the worst fallout. Bankrolled by generous agricultural subsidies, the United States flooded the Mexican market with corn priced lower than the cost of production. Consequently, some 2 million Mexican farmers lost their land, much of which had been passed down for generations. Where U.S. jobs did move, it was due to the presumption of lower wages and workplace safety standards: Where U.S. autoworkers earned $34 an hour, those same jobs once moved to Mexico paid workers $2 an hour.

Some will argue that while desirable, open borders are simply utopian. Progressives need to do better. There is simply no moral case for restricting people’s freedom of movement, much less on stolen land.

While pundits wax eloquent on the dangers of open borders, the rich reap the benefits. Corporations enjoy unrestricted freedom of movement, packing up at first sign of unionization, while having access to a cheap and expendable labor pool. Immigrants are demonized for pushing wages down, letting businesses avoid scrutiny for historic gaps in worker-boss pay ratios.

In accepting the premise that migration drives down living standards, Sanders misses an important opportunity to call corporate greed to account and stand in solidarity with immigrant communities.