When Donald Trump first entered the Republican presidential primary, there was a widespread impulse to treat him as if he were a joke candidate. The Huffington Post, for one, famously announced that it would cover Trump only as entertainment news. Yet there’s diminishing entertainment value to be found in Trump’s campaign, as he continues not only to dominate the polls on the Republican side but also to set the very terms of debate, with his rivals echoing and endorsing his strident xenophobia. Thanks to Trump, this has become a political contest about national identity, with the core question being, “What sort of country is America?”

In the Islamophobic turn that Trump and the GOP have taken since the Paris attack, the question of national identity has taken on a new urgency. The radical proposals now being put forward by Trump (and frequently echoed in only slightly less virulent form by his rivals) would define the United States as a much less tolerant and pluralistic country, one in which an entire religion could be cast under a shroud of state-sponsored suspicion. Perhaps the saving grace of this election is that the two major Democratic candidates, Hillary Clinton and Bernie Sanders, have recognized the severity of Trump’s challenge to fundamental questions of national identity and have answered his challenge with strong rebukes arguing for a more tolerant America.

The far-reaching nature of Trump’s proposals cannot be shrugged off. Interviewed yesterday by NBC, he said he “would certainly implement” a mandatory national database for Muslim Americans. When asked how this would be different from Nazi policies in the 1930s and 1940s to register Jews, Trump curtly replied, “you tell me.”

In an interview with Hunter Walker of Yahoo, Trump didn’t shy away from acknowledging that he wants a radical change in how the nation treats its Muslim American minority. “We’re going to have to do things that we never did before,” Trump said. “And some people are going to be upset about it, but I think that now everybody is feeling that security is going to rule. And certain things will be done that we never thought would happen in this country in terms of information and learning about the enemy. And so we’re going to have to do certain things that were frankly unthinkable a year ago.”

On the Republican side, Trump’s xenophobia has met with near-complete capitulation. True, John Kasich and Jeb Bush have expressed mild reservations, and have criticized Trump’s tone; on Friday morning, Bush accused Trump of manipulating people’s angst and their fears. But on matters of policy, they have both shifted in Trump’s direction. Kasich has called for a halt to Syrian refugees coming into America, and Bush says that only Syrian Christians refugees should be accepted. Meanwhile, Trump’s calls to close the gates to Syrian refugees have become the GOP party line. “Everyone is now saying how right I was with illegal immigration & the wall,” Trump tweeted on Thursday. “After Paris, they’re all on the bandwagon.”