ATLANTA—Celebrity real-estate developer Donald Trump has called illegal immigrants "rapists" and has denigrated a war-hero senator, but it was his graphic insult of Fox News host Megyn Kelly that got him "disinvited" from an influential conference of conservative activists.

RedState editor and conference host Erick Erickson told the hundreds gathered to hear from presidential candidates Saturday morning that he has allowed Trump a good deal of "latitude" thus far but that his claim that Kelly asked him hard questions during Thursday night's GOP debate because she was menstruating had crossed a line.

"It is not political-correctness; it's common decency," Erickson said and warned that this sort of distracting controversy would be far worse than the secretly recorded "47 percent" remarks by 2012 presidential nominee Mitt Romney. "We will not gain the White House if we are not going to be happy warriors."

Trump, who leads in most polls for the GOP presidential nomination, was to have closed theRedState Gathering with an appearance at the group's tailgate party Saturday evening. Late Friday, though, Erickson said he called the Trump campaign to ask whether Trump would apologize for or clarify his remarks about Kelly on CNN a couple of hours earlier.

In a phone-in interview with CNN, Trump complained about Kelly's questioning during the Cleveland debate. "You know, you could see there was blood coming out of her eyes, blood coming out of her wherever," Trump said. "In my opinion, she was off base."

Saturday morning, the Trump campaign released a statement saying that "wherever" actually referred to Kelly's nose. "Only a deviant would think anything else," the statement said, which went on to call Erickson a "total loser."

Earlier Saturday, Trump had released a statement blaming "political-correctness" on Erickson's part:

"This is just another example of weakness through being politically correct. For all of the people who were looking forward to Mr. Trump coming, we will miss you. Blame Erick Erickson, your weak and pathetic leader. We'll now be doing another campaign stop at another location."

Erickson, though, got strong applause as he announced his decision. "I actually think it's really weak and pathetic to take a tough question from a journalist and assume she's having her period and that's why she asked a tough question," he said. "It's disrespectful to Megyn Kelly, it's disrespectful to female journalists, it's disrespectful to ladies in general, and I don't want my daughter in the room with Donald Trump [Saturday] night, so he's not invited. I'm sorry."

This latest episode provides Erickson and other conservative leaders an easy justification to publicly disown Trump, whom they regard as an entertainer rather than a serious politician and whose conservative bona fides have long been suspect.

During his June announcement speech, Trump called illegal immigrants from Mexico "rapists," although he allowed that some might be good people. Last month, Trump said the reason Sen. John McCain was considered a war hero was because he was captured and that Trump preferred people who weren't captured.

But illegal immigrants are tremendously unpopular among the conservative Republican base and, in any event, cannot vote. Likewise, McCain—who was tortured for years in a North Vietnamese prisoner-of-war camp and still has limited use of his arms because of it—is unpopular with likely primary voters.

In contrast, Megyn Kelly is a well-liked host at Fox, a favorite news source among Republicans. And women make up a majority of Republican voters and voters generally.

Even so, Trump's big polling numbers and success in tapping into populist anger among Republican primary voters could make some Republican candidates less than eager to criticize Trump, particularly those who hope to pick up his supporters after Trump has faded.

The only woman in the GOP presidential field, former Hewlett-Packard CEO Carly Fiorina denounced Trump Friday night on Twitter, which Wisconsin Gov. Scott Walker cited on Saturday morning.

"There's no excuse for Trump's comments," Walker wrote, adding that Kelly "is a tough interview. Being POTUS is tougher. @GOP candidates & media need to get back to how we're going to turn US around."

Former Texas Gov. Rick Perry similarly criticized Trump's comments. "Donald Trump has proven once again that he doesn't have the temperament to hold our nation's highest office. Attacking veterans, Hispanics, and women demonstrates a serious lack of character and basic decency, and his comments distract from the serious issues facing our country," he said. 

Sen. Lindsey Graham, meanwhile, released a statement praising Erickson.

"I applaud Erik Erickson for doing the right thing when he disinvited Donald Trump from a gathering of Republican activists," Graham's statement said. "As a party, we are better to risk losing without Donald Trump than trying to win with him. Enough already with Mr. Trump."

The first presidential contender to appear at RedState Saturday morning, however, was unwilling to take that risk.

"There's plenty of people who can talk about Donald Trump. I'm the only one who can talk about what Mike Huckabee is doing running for president," the former Arkansas governor told reporters. Huckabee praised Kelly as smart and professional, but he declined to criticize Trump or to call on him to apologize. "I'll have to leave that up to him."

Huckabee grew irritated as the questions about Trump persisted and said it was not his job to give advice to the other candidates. "The Republican Party is not engaged in a war on women. The Republican Party is not engaged in saying things about Megyn Kelly. One individual is," Huckabee said.

And Ted Cruz, who last month met with Trump in New York City and has refused to criticize his previous controversial comments, on Saturday declined to discuss Trump at all, other than to say that he, too, admired Kelly. "I'm not going to engage in the back and forth on personalities," he said.

But the third presidential candidate to appear Saturday, former Florida Gov. Jeb Bush, went out of his way to praise Erickson's call.

"Give me a break. I mean, do we want to win? Do we want to insult 53 percent of all voters? What Donald Trump said was wrong. That is not how we win elections," Bush said. "So your decision I think was the right one, and Mr. Trump ought to apologize."