At a rally in Iowa on Wednesday, Donald Trump tried to whip up the crowd by asking anyone who was a Christian conservative to raise their hand. The crowd cheered. The Republican nominee then made a strange follow-up request: “Raise your hand if you’re not a Christian conservative. I want to see this, right? Oh there’s a a couple people, that’s all right,” the candidate said as he brusquely waived his right hand. “I think we’ll keep them, right? Should we keep them in the room, yes? I think so.” He was in a jovial mood as he said all this, but if he was making a joke, it had a sinister undertone. Trump, after all, is running to be president of the pluralistic United States, but here he is suggesting that it might good to apply a religious test and to kick out anyone who wasn’t a Christian conservative. The remarks were a reminder of Tump’s notorious call to ban Muslims from entering the country, if not also of his Fox and Friends appearance on September 19 when he described Muslim immigrants as a “Trojan Horse” who were bringing a “cancer from within” to America.

Trump habitually sees the world in stark “us versus them” terms, and makes wholesale denunciations of entire ethnic groups. Which inevitably raises the question, “Is Donald Trump a fascist?”

An unresolved debate on that query has taken place since Trump launched his candidacy last summer. Writers like Adam Gopnik in The New Yorker and Robert Kagan in The Washington Post have answered “yes,” citing as evidence Trump’s ethnic demagoguery, his scorn for and ignorance of the existing democratic system, his indulgence in conspiracy thinking, and his open admiration of autocrats like Vladimir Putin. Other analysts, perhaps most compellingly Dylan Matthews in Vox, counter by noting that Trump’s movement differs from historical fascism in key ways: Trump has organized no paramilitary groups to subvert liberal norms, he hasn’t openly rejected democracy (although perhaps has tried to delegitimize the system by saying it is rigged), and he does not celebrate violence for the sake of violence (even though there is evident glee in his calls to beat up protesters and to torture enemy combatants).

But “is Donald Trump a fascist?” is not a yes/no question. Fascism has never been a fixed creed; it’s a syndrome, a series of intertwined tendencies.

One of the hallmarks of fascism is its opportunism, the willingness of fascist leaders to shift depending upon the needs of the moment. As the social theorist Franz Neumann noted in his 1944 book Behemoth, “National Socialism’s ideology is constantly shifting. It has certain magical beliefs—leadership adoration, supremacy of the master race—but [it] is not laid down in a series of categorical and dogmatic pronouncements.” Building on this insight, historian Robert Paxton argued in his 2004 book Anatomy of Fascism that “fascism does not rest explicitly upon an elaborated philosophical system, but rather upon popular feelings about master races, their unjust lot, and their rightful predominance over inferior people.”