As the United States and Europe condemned Russia for its invasion of Ukraine, Sasa Bozic responded by opening the Putin Café in the Bosnian city of Banja Luka, decorating it with a mannequin of the Russian president — a foot taller than Vladimir V. Putin is in real life.

Today, with much of Europe horrified at President Trump’s attack on President Volodymyr Zelensky of Ukraine in the Oval Office, Mr. Bozic has a new project: a motel and restaurant complex called “Trump and Putin’s Place.” He plans to open it this summer.

Paying tribute to Mr. Trump and Mr. Putin, Mr. Bozic said, is not political — just “a “marketing trick” that works in Banja Luka. Since the 1989 collapse of Communism in Eastern Europe, many in the mostly ethnic Serb city and surrounding region have looked favorably on Russia and with hostility on an American-led order in Europe that Mr. Trump appears intent on upending.

A Biden Café, Mr. Bozic said, would never work, even less an eatery named after President Zelensky, but “everyone here likes Putin and Trump.”

Banja Luka is the capital of Republika Srpska, a Serb-controlled region of Bosnia and Herzegovina that was born from the ethnic cleansing of the Balkan wars of the early 1990s. That violence more than three decades ago punctured hopes that the demise of Communism would open a new era of prosperity and harmony. It gave an early foretaste of the appeal and destructive power of ethnonationalism, a force now resurgent around the world.