In the 1990s, after the Soviet Union collapsed, ideological conservatives and civilizational conservatives parted ways. The clearest example was the former Yugoslavia. In the 1990s, Serbs brutalized the largely Muslim breakaway republic of Bosnia. Ideological conservatives like Robert Kagan urged NATO to intervene in the name of human rights. Cultural conservatives like Buchanan wondered why the U.S. was going to war to defend Muslims against Christians. Ideological conservatives saw Russia, Serbia’s traditional ally, as defending tyranny and ethnic cleansing. Cultural conservatives saw Russia as defending Christendom.

For a while, 9/11 papered over these divisions. Bush largely justified the “war on terror” in ideological terms: as a struggle against a new totalitarian foe that had “hijacked” Islam. In this depiction, ordinary Muslims living in places like Afghanistan and Iraq were not the equivalent of Nazis or communists; they were the equivalent of the people who those previous totalitarian foes had held in bondage. Civilizational conservatives considered Bush naïve. Franklin Graham, who delivered the prayer at Bush’s first inauguration, repeatedly described Islam itself as wicked. But while their justifications for the “war on terror” differed, both ideological and civilizational conservatives backed Bush’s military adventures in Afghanistan and Iraq.

Bush left behind a GOP establishment dominated by ideological conservatives. In 2008 and 2012, McCain and Romney both resisted describing Islam itself as a threat. Romney described authoritarian Russia as America’s greatest geopolitical foe. But during both election cycles, more populist, civilizationally-oriented, conservatives—Michelle Bachmann, Herman Cain, Sarah Palin, Mike Huckabee, Ben Carson—kept attacking Islam itself.

When he ran for president, Trump realized that on Islam, as on trade, Republican elites were out of step with the Republican base. Trump distinguished himself from his rivals not by proposing a different strategy against ISIS. He distinguished himself by suggesting that the problem was not merely ISIS, or even “radical Islam,” but Muslims in general. Republican leaders reacted to Trump’s call for banning Muslim immigration to the U.S. with revulsion. But, according to surveys, more than seven in 10 GOP voters supported it.

Trump also broke with his establishment rivals by taking a softer line on Russia. Maybe financial interests motivated him. Maybe he just likes authoritarian tough-guys. Whatever the reason, the deviation seemed politically dangerous given the overwhelming hostility to Putin among GOP foreign-policy elites. But Trump’s pro-Putin line hasn’t hurt him. In fact, Republicans as a whole have grown markedly less anti-Russian since 2014.

Partly, they’re aping Trump. But there’s something deeper at work. Ideological conservatives loathe Putin because he represents an authoritarian challenge to the American-backed order in Europe and the Middle East. But many civilizational conservatives, who once opposed the Soviet Union because of its atheism, now view Putin’s Russia as Christianity’s front line against the new civilizational enemy: Islam. Among the alt-right, Putin is a very popular man. He’s popular because he resists the liberal, cosmopolitan values that Muslims supposedly exploit to undermine the West. Richard Spencer, who was until recently married to a pro-Putin Russian writer, has called Russia the “sole white power in the world.” Matthew Heimbach, another prominent figure in the alt-right, recently told Business Insider that “Russia is the leader of the free world.” In 2013, Pat Buchanan penned a column entitled, “Is Vladimir Putin a paleoconservative? In the culture war for mankind’s future, is he one of us?”