America has become a less welcoming place for refugees under Donald Trump.

The US president has considerably slowed down their entry into the country, citing security concerns. His administration also is targeting refugees already in the US, including Vietnamese immigrants who fled their country at the end of the Vietnam War. Many of them are legal residents, and protected by an agreement between the US and Vietnam, but have been slated for deportation because of past criminal convictions.

In turning refugees away, Trump might be squandering an asset that could help solve another issue he has vowed to tackle: the US’s massive trade deficit. Trump’s strategy to cut it has mostly centered on blocking imports, but his goal also could be achieved by increasing exports. And refugees—and immigrants in general—make for adept trade representatives, according to the findings of a paper published in The Economic Journal earlier this year.

It looked at the case of Vietnamese boat people, the hundreds of thousands of refugees who came to the US starting with the fall of Saigon in 1975 until the early 1990s. Because of a US-imposed trade embargo on Vietnam until 1994, the researchers were able to track whether the number of Vietnamese in any given state had any impact on that state’s levels of exports to Vietnam from that point onward.

They found exports to Vietnam from 1995 to 2000 grew the most in states with bigger Vietnamese populations. According to the researchers’ calculations, a 10% rise in the number of Vietnamese lifted exports by 4.5% to 14%.

Another study, published this week by the National Bureau of Economic Research, also shows that immigrants are inclined to export. That paper, based on a survey of business owners, found that around 8% of US immigrant-owned firms exported in 2012, compared to about 4% of native firms.

Selling abroad comes easier to immigrants because of their ties to their country of origin, and their understanding of how markets work there, researchers say. Luckily for Trump, there’s no shortage of immigrants he could enlist from China and Mexico, two countries he has berated for selling more to the US than they buy, for their expertise in how to sell more to those places.

Indeed, “targeting specific migrants from specific countries to boost exports is not too far-fetched as a policy,” says Pierre-Louis Vézina, one of the authors of the study on the Vietnamese refugees. If a firm wants to export to Japan, for example, having a network of Japanese business consultants, lawyers, and marketers would help—and so would having an immigration policy that allows them into the country.