A supporter holds up a sign reading "deport illegals now" as U.S. President-elect Donald Trump speaks during a campaign rally at the Bojangles Coliseum in Charlotte, N. C., July 24. AFP-Yonhap

Donald Trump's hostile approach to immigration was one of the key reasons that helped him recapture the White House. A surge in the number of migrants crossing into the U.S. illegally at its southern border during the Joe Biden administration apparently raised worries among many voters and hardened their views on immigration.

Experts say this election result offers valuable lessons for Korea's policymakers who seek to expand the number of foreign workers as part of their strategies to counter labor shortages exacerbated by the country's aging and shrinking population.

For a country facing a choice between that and accepting its slow economic decline like Japan, increasing the number of foreign residents may be inevitable, they said. But pushed bluntly or hastily, such a policy could give rise to major anti-immigrant political forces, as it is seen across the U.S. and Europe, they warned.

"Some countries accept immigrants and foreign workers for economic benefits. But as their influence grows, citizens could face a host of issues such as more competition for jobs, a rise in crime, growing anti-immigrant sentiment and politicians seeking to capitalize on it," Lee Joon-han, a professor of political science at Incheon National University, told The Korea Times, Thursday. "Korea is no exception to that risk."

So far, no such political parties have won any seats at the country's National Assembly. But there have been such attempts. Park Jin-jae of the Liberty Unification Party, a fringe political party, ran for a parliamentary seat in Daegu in April, with campaign messages focused on "prioritizing and protecting" Korean citizens. Deporting all immigrants without legal status and repealing social benefits for multicultural families were among his key election pledges.

The following month, police said 10 members of a Daegu-based nationalist vigilante group, founded by Park, were being investigated for "arresting" foreign residents without any legal authority.

The emergence of such political figures and their counterforces could lead the country to a new political environment, where immigration issues would draw more attention and passion, Lee said.

"This poses a particularly high risk for a country where permanent foreign residents can vote in local elections," he said. "Soon, we may see politicians promoting policies specifically targeting such residents in areas where many of them live."

But geographically, experts said Korea, compared with the U.S. and many European nations, is in a better position to manage its population. Surrounded by the sea and the inter-Korean border, the country's only lengthy land border is heavily militarized on both sides.

"Most undocumented foreign residents here are those who have overstayed their visas. This means that Korea is in a better position to manage them," said Kim Joon-sik, the honorary chairman of Asian Friends, a Seoul-based NGO. "I think the government should step up efforts to develop strategies to better manage foreign residents here and coexist with them more while it can ... the country's economic dependence on them is now growing fast, which could be a political issue in the near future. So far, I don't see any sign of such efforts. That's very unfortunate."