Immigration isn’t without its negative effects, especially on Americans who lack a high school diploma, according to George Borjas, a professor of economics and social policy at Harvard's John F. Kennedy School of Government. In a 2013 report published by the immigration-restrictionist Center for Immigration Studies, Borjas calculated that immigrants might have depressed the wages of native-born high school dropouts by 6 percent between 1990 and 2010, mainly due to foreigners who’d arrived illegally.

But immigration, on the whole, bolsters the workforce and adds to the nation’s overall economic activity. Look at the impact on cities that attract the most foreign-born residents. New York, Los Angeles, Chicago, and Houston are all major immigrant destinations and also economic powerhouses, accounting for roughly one-fifth of the country’s gross domestic product. In New York, immigrants made up 44 percent of the city's workforce in 2011; in and around Los Angeles, they accounted for a third of the economic output in 2007.

Immigrants tend to contribute more to the economy once they’ve learned English and become citizens. A few cities—notably, New York—have a long history of ushering immigrants into the mainstream society and economy. Other parts of the country have less experience with newcomers but are learning to adapt.

Take Nashville, for instance. As recently as 2009, immigrants living in the Tennessee capital had reason to worry. A conservative city council member proposed amending the municipality’s charter to require that all government business be conducted in English, allegedly to save money. This raised hackles. “Would the health department be allowed to speak Arabic to a patient?” or so The Tennessean, Nashville's leading newspaper, wondered. “Could a city-contracted counselor offer services in Spanish?”

The voters apparently wondered, too, for they soundly defeated the English-only amendment, which had earned the enmity of businesses, religious organizations, and advocacy groups. “A significant moment in the city’s history when it comes to immigration,” recalls Nashville’s mayor, Karl Dean, a Democrat who had recently taken office. “Since that moment, the city really hasn’t looked back.”

The foreign-born population in the Nashville metropolitan area has more than doubled since 2000; immigrants accounted for three-fifths of the city’s population growth between 2000 and 2012, and now constitute an eighth of all Nashville residents. When President Obama delivered a speech on immigration last December, he did it in Nashville. The city famed as the nation’s country music capital now boasts the largest U.S. enclave of Kurds, along with increasing numbers of immigrants from Myanmar and Somalia.

They’ve been drawn to Nashville’s booming economy, which has ranked among the fastest-growing in the nation in recent years. But they’re not only benefiting from the local prosperity—they’re contributing to it. Immigrants are twice as likely as native-born Nashville residents to start their own small businesses, according to data compiled by the Partnership for a New American Economy. They also play an outsized role in important local industries, including construction, health care, and hotels.