At first glance, last week’s Republican presidential debate revealed a party fractured over America’s role in the world. Ron DeSantis said he wouldn’t support additional aid to Ukraine unless Europe does more. Vivek Ramaswamy said he wouldn’t arm Ukraine no matter what. Chris Christie, Mike Pence and Nikki Haley, all staunch defenders of Kyiv, pounced. Within minutes, the altercations were so intense that the moderators struggled to regain control.But amid the discord, one note of agreement kept rising to the surface: that the true threat to America comes from Beijing. In justifying his reluctance to send more aid to Ukraine, Mr. DeSantis said he’d ensure that the United States does “what we need to do with China.” Mr. Ramaswamy denounced aiding Ukraine because the “real threat we face is communist China.” Ms. Haley defended such aid because “a win for Russia is a win for China.” Mr. Pence said Mr. Ramaswamy’s weakness on Ukraine would tempt Beijing to attack Taiwan.Regardless of their views on Ukraine, Republicans are united in focusing on China. They are returning to the principle that many championed at the beginning of the last Cold War. It’s neither internationalism nor isolationism. It’s Asia First.When Americans remember the early Cold War years, they often think of Europe: NATO, the Marshall Plan, the Truman Doctrine, which justified aiding Greece and Turkey. But for many leading Republicans at the time, those commitments were a distraction: The real menace lay on the other side of the globe.Senator Robert Taft, nicknamed “Mr. Republican” because of his stature in the party, opposed America’s entrance into NATO and declared in 1948 that “the Far East is ultimately even more important to our future peace and safety than is Europe.” The following year, Senator H. Alexander Smith, a Republican on the Foreign Policy and Armed Services Committee, warned that while the Truman administration was “preoccupied with Europe the real threat of World War III may be approaching us from the Asiatic side.” William Knowland, the Senate Republican leader from 1953 to 1958, was so devoted to supporting the Nationalist exiles who left the mainland after losing China’s civil war that he was called the “senator from Formosa,” as Taiwan was known at the time.Understanding why Republicans prioritized China then helps explain why they’re prioritizing it now. In her book “Asia First: China and the Making of Modern American Conservatism,” the historian Joyce Mao argues that Cold War era Republicans’ focus on China stemmed in part from a “spiritual paternalism that arguably carried over from the previous century.” In the late 19th century, when the United States was carving out a sphere of influence in the Pacific, China, with its vast population, held special allure for Americans interested in winning souls for Christ. The nationalist leader Chiang Kai-shek and his wife, who were Christians themselves, used this religious connection to drum up American support — first for their war against Communist rivals on the Chinese mainland and then, after they fled to the island of Taiwan, for their regime there.Many of America’s most influential Asia Firsters — like the Time magazine publisher Henry Luce — were either the children of American missionaries in China or had served as missionaries there themselves. The John Birch Society, whose fervent and conspiratorial brand of anti-Communism foreshadowed the right-wing populism of today, took its name from an Army captain and former missionary killed by Chinese communists at the end of World War II.Today, of course, Americans don’t need religious reasons to put Asia first. It boasts much of the world’s economic, political and military power, which is why the Biden administration focuses on the region, too. In Washington, getting tough on China is now a bipartisan affair. Still, the conservative tradition that Ms. Mao describes — which views China as a civilizational pupil turned civilizational threat — is critical to grasping why rank-and-file Republicans, far more than Democrats, fixate on the danger from Beijing.In March, a Gallup poll found that while Democrats were 23 points more likely to consider Russia a greater enemy than China, Republicans were a whopping 64 points more likely to say the reverse. There is evidence that this discrepancy stems in part from the fact that while President Vladimir Putin of Russia casts himself as a defender of conservative Christian values, President Xi Jinping leads a nonwhite superpower whose regime has spurned the Christian destiny many Americans once envisioned for it.In a 2021 study, the University of Delaware political scientists David Ebner and Vladimir Medenica found that white Americans who expressed higher degrees of racial resentment were more likely to perceive China as a military threat. And it is white evangelicals today — like the conservative Christians who anchored support for Chiang in the late 1940s and 1950s — who express the greatest animosity toward China’s government. At my request, the Pew Research Center crunched data gathered this spring comparing American views of China by religion and race. It found that white non-Hispanic evangelicals were 25 points more likely to hold a “very unfavorable” view of China than Americans who were religiously unaffiliated, 26 points more likely than Black Protestants and 33 points more likely than Hispanic Catholics.This is the Republican base. And its antipathy to China helps explain why many of the right-wing pundits and politicians often described as isolationists aren’t isolationists at all. They’re Asia Firsters. Tucker Carlson, who said last week that American policymakers hate Russia because it’s a “Christian country,” insisted in 2019 that America’s “main enemy, of course, is China, and the United States ought to be in a relationship with Russia aligned against China.” Mr. Ramaswamy, who is challenging Mr. DeSantis for second place in national polls, wants the United States to team up with Moscow against Beijing, too.And of course, the Republican front-runner for 2024, former President Donald Trump — deeply in tune with conservative voters — has obsessed over China since he exploded onto the national political stage eight years ago. Mr. Trump is often derided as an isolationist because of his hostility to NATO and his disdain for international treaties. But on China his rhetoric has been fierce. In 2016, he even said Beijing had been allowed to “rape our country.”Republicans may disagree on the best way forward in Ukraine. But overwhelmingly, they agree that China is the ultimate danger. And whether it’s Mr. Trump’s reference earlier this year to his former secretary of transportation as “Coco Chow” or House Republicans implying that Asian Americans in the Biden administration and Congress aren’t loyal to the United States, there’s mounting evidence that prominent figures on the American right see that danger in racial terms.That’s the problem with Republicans’ return to Asia First. Many in the party don’t only see China’s rise as a threat to American power. They see it as a threat to white Christian power, too.Peter Beinart (@PeterBeinart) is a professor of journalism and political science at the Newmark School of Journalism at the City University of New York. He is also an editor at large of Jewish Currents and writes The Beinart Notebook, a weekly newsletter.The Times is committed to publishing a diversity of letters to the editor. We’d like to hear what you think about this or any of our articles. Here are some tips. 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