Trump has not, so far, thoroughly disavowed the creation of a national registry of Muslims. Photograph by Marvin Gentry/Reuters

Donald Trump was just telling a crowd in Birmingham, on Saturday, about his standing in the latest polls—“Big! Big!”—when he paused. "Do I hear somebody over there?" Trump asked, shaking his head. He hadn't even reached the part of the speech where he would explain, somewhat, how the press had lied about his interest in databases of Muslims, and why we needed "surveillance of certain mosques,” and here someone, a voice calling out in the crowd, was interrupting him. "You know, you have one guy over there shouting, we have thousands of people—and you'll read about him tomorrow. They'll say ooohhh—the room had a picket! Yeah, get him the hell out of here will you please? Get him out of here. Throw him out!" There was applause. Up in the stands, as security guards led the heckler, a black man, away, members of the audience set on him, shoving, kicking, and, in one case, punching. A CNN video caught some of the violence, and it made two things clear: without the security guards, it could have been profoundly worse; and this was a crowd that was ready to follow Trump, and get the people out whom he wanted out.

On stage, Trump was remembering a heckler at another event "who was seriously obese—he complained when I mentioned that food stamps—we have a lot of people on food stamps," and then he said he didn't "want the people from Syria coming in because we don’t know who they are." His thoughts seemed to be joined, logically or illogically, under the rubric, "This time it's not about 'nice.' " Then he paused again, and raised his hand to his forehead like a visor, as though trying to spot the sidewalk from a penthouse.

"Hey, you want to see something funny?" Trump said. "Look at those cameras, they're turned around. They're following the few people that are being thrown out. ... Look at those bloodsuckers!" All the press was interested in, he said, was people "being thrown out on their ass." This reminded him about what "dishonest people" they were, and about how there were lies on the front page of the New York Times, "And that had to do with whether or not we register people, O.K.?"

The Times, in the first paragraph of an article on Saturday, referred to Trump's "call for a mandatory registry of Muslims in the United States." In fairness, there was some ambiguity in Trump's first two exchanges on the subject, though in all readings their ugliness is undeniable. In one, according to a Yahoo News story, on Thursday, its reporter asked Trump about setting up such a database or having Muslims carry special identification. Trump, in Yahoo News's words, "wouldn't rule it out," saying, in his own words, "We’re going to have to—we’re going to have to look at a lot of things very closely.” Later, an NBC News reporter caught up with Trump on the campaign trail and, as Trump was walking out at the end of an event, they had this exchange:

NBC: Should there be a database or system that tracks Muslims in this country?

Trump: There should be a lot of systems, beyond databases. I mean, we should have a lot of systems. And today you can do it. But right now we have to have a border, we have to have strength, we have to have a wall, and we cannot let what’s happening in this country happen any longer.

NBC: But that’s something your White House would want to implement?

Trump: Oh, I would certainly implement that. Absolutely.

NBC: What do you think the effect of that—how would that work?

Trump: It would stop people from coming in illegally. We have to stop people from coming into our country illegally.

So which would he "absolutely" implement—the wall or the database? Trump's spokesman later suggested that Trump misheard the question, and meant the latter. But when the reporter went on to ask if the plan would be to "go to mosques and sign people up," Trump said, "You sign them up at different—but it’s all about management." Was he talking about Syrian refugees, Muslim immigrants from any country, or Muslim citizens in general? The better question might be whether Trump makes any real distinction between those categories. The answer might be no better than the one Trump gave when he was asked about the difference between his proposals and some of the policies in Nazi Germany: "You tell me."

Trump's defense has not, so far, involved thoroughly disavowing a national registry of Muslims. This alone should be shocking, quite apart from his fear-mongering about mosques and refugees, subjects on which he seems to be getting a relative pass, in part because his opponents have not exactly taken heroic stands on the issue. "I'm a big fan of Donald Trump's. But I'm not a fan of government registries of American citizens," Ted Cruz said, suggesting mostly that he was not a fan of distancing himself from Trump. A few days earlier, Cruz had called for excluding non-Christian refugees from Syria. Jeb Bush made similar suggestions, while managing to say that a religious registry would be “wrong.” Ben Carson seemed surprised, and a little alarmed, that there wasn't already such a database “on every citizen.” Marco Rubio said that a database was "unnecessary," according to the Associated Press, which is not the same as “unacceptable.” When the Fox News host Megyn Kelly asked Rubio about closing mosques, he said, “It’s not about closing down mosques. It’s about closing down any place, whether it’s a café, a diner, an Internet site, any place where radicals are being inspired.” Would that apply to a Donald Trump rally?