On Friday, just a few hours after the United Kingdom voted to leave the European Union, Donald Trump sent out an email to raise money off the referendum.

“Voters in the United Kingdom chose to leave the flawed and failing European Union and reassert control over their borders, politics and economy, taking a brave stand for freedom and independence,” he wrote. “They put the United Kingdom first, and they took their country back. With your help, we’re going to do the exact same thing on Election Day 2016 here in the United States of America.”

Ending with a call to block the “corrupt Washington establishment” and a big red donate button, the email tried to draw a clear parallel between the unease reflected in the British vote and the fears long expressed by Trump that the United States had lost control of its borders and given away control of its economy to foreign powers.

Will the Brexit vote embolden like-minded American voters and add to Trump’s strength? There’s little evidence that political expression in the United Kingdom has much effect here.

“British people pay much more attention to what’s going on in the U.S. than vice versa,” said Scott Blinder, a professor of political science at the University of Massachusetts at Amherst who has lived in both the U.S. and the U.K. “So I doubt many Americans — beyond those who are involved in politics for a living — will be thinking at all about Brexit or UKIP (the anti-Europe U.K. Independence Party) by the end of this week.”

Nonetheless, Trump voters and Brexit supporters do share some common political concerns — a sense that it’s necessary to protect borders, culture and the economic interests of native-born majority-culture citizens. Professor Matthew Goodwin of the University of Kent, in Canterbury, England, points out that in both the U.S. and the U.K., many workers “have not had a raise for at least 10 years” in inflation-adjusted terms.

“You can begin to understand, if not empathize with, their economic pessimism,” he said in an interview. “In the five areas where Brexit was strongest, the median income was around £18,000 [around $23,760], while in the five areas where support for Brexit was weakest, the median income was around £35,000 [$46,200].”

The U.S. and the U.K. have about the same percentage of foreign-born residents: 13 percent in the U.K. and 14 percent here. Many of the U.K.’s immigrants have come through the open borders granted by the EU; net migration to the U.K. has doubled since 2000, and 1 in 3 immigrants are from other EU countries. Citizens of EU nations plus three others, collectively known as the European Economic Area (EEA), can work in the U.K. They would be most affected by the Brexit, with the largest number of workers coming from Poland, followed by Ireland and Germany.

Although legal migrants working in the U.K. from other parts of the European Union are not directly parallel to America’s undocumented immigrants, resentment of workers from other nations has buoyed right-wing politics on both sides of the Atlantic, raising the question of whether there now is a trans-Atlantic nativist moment.

“If there has been a feedback loop between U.S. and European nativism, it has been in the impression nativists on both sides of the Atlantic got that it’s kicking off everywhere,” said Tobias Dürr, a political scientist and co-founder of the Progressive Zentrum, a left-leaning nonprofit think tank in Berlin.

Immigration was clearly a key factor in last week’s vote. In December, Goodwin co-wrote a paper for the Royal Institute of International Affairs, also known as Chatham House, that proved prescient. The research analyzed responses from more than 30,000 respondents to the 2015 British Election Study, and categorized citizens considering the referendum into “inners” (Remain), “outers” (Leave), and undecideds. While only 1 in 5 “inners” felt immigration was bad for the economy, nearly 7 in 10 “outers” felt that way. The survey also asked whether immigration was undermining British culture. Seventy-three percent of “outers” felt it did hurt the culture, compared with 28 percent of “inners.” The report added: “In many respects, undecided voters — who may yet decide the outcome of the referendum — look more like the ‘outers’ than the ‘inners.’”

There are already a few initial signs that some Brits who voted to leave Europe now regret their choice. One online poll released Sunday estimated that 7 percent of those who voted to leave now regret doing so, the equivalent of 1.2 million people. (In the final vote, 1.27 million more people voted to leave the EU than to stay.)

With some “Leave” politicians already walking back promises to curb immigration and spend more money on the National Health Service, Dürr predicts the Brexit hangover could help American voters understand the costs of isolation.

The regret “could take some further steam out of the Trump movement,” Dürr said. “So in the weeks to come I think we could see the opposite of nativists emboldening each other across the Atlantic.”

But that assumes American voters are paying attention.

CORRECTION (June 28, 1:30 p.m.): An earlier version of this article included calculations that were based on an incorrect vote total in the Brexit referendum. In the final tabulation, 1.27 million more people voted to leave the EU than to stay, not 1.2 million. And the 7 percent of the “Leave” voters who said they regret their vote in an online survey is the equivalent of 1.2 million people, not 1.1 million. (Additionally, 4 percent of those who voted to remain also said they regret it, the equivalent of 600,000 people.)