Donald Trump: Is time up for his 2016 campaign for Republican candidacy?

Mr Trump dominated the RedState conference, even though he was disinvited

He's been running a campaign that defies political gravity. Every time experts predict the New York mogul is about to plummet, he instead reaches new heights in opinion polls.

But if this latest self-inflicted controversy is going to be different, if Mr Trump's derisive comments about Fox News presenter Megyn Kelly are what finally breaks the back of his campaign, then the track of his fall will have been matched by the shifting opinions expressed at the conservative RedState Gathering of grassroots activists in Atlanta, Georgia.

The Republican powers have never been on Mr Trump's side. To them he represents a distraction from attempts to paint a broader, more inclusive face on their party.

But the New York tycoon has tapped into an anger and resentment among rank and file conservatives, who feel that establishment politicians are ignoring their concerns and diminishing their issues.

"When politicians are just starting out, they're happy to meet the grassroots and ask for money," said Randy Daniel, an Atlanta-area dentist who attended the two-day conference.

But once they get to Washington, he continued, they get big-lobbyist and big-business money and "we never hear from them again".

Many of the attendees at this conference said they entered the weekend with an open mind on Mr Trump.

While they weren't necessarily sold on him as the Republican front-runner, they cheered and hooted at his antics while watching Thursday night's Republican candidate debate.

Megyn Kelly's questioning of Mr Trump was not welcomed by everyone

Some even disagreed with Ms Kelly for sharply questioning Mr Trump on his past comments about women.

"It was a mean question," said Sandy Rabe of Cincinnati, Ohio. "I expected more of Fox."

But Mr Trump upped the voltage on Friday on Twitter and in television interviews, ending the night with his "blood coming out of her wherever" comments about Ms Kelly.

By midnight, the candidate had been uninvited from a scheduled Saturday night keynote appearance at the conference, and the next day the tone among attendees had changed considerably.

'Unforced error'

Instead of cheering Mr Trump, the crowd now cheered RedState impresario Erick Erickson's announcement that the candidate had defied "common decency".

They groaned and booed as Mr Erickson read texts of insulting emails he had received from Trump supporters, who called him a liberal stooge and directed misogynistic invective at Ms Kelly.

A survey of the conference attendees by the end of the day painted a picture of a grassroots conservative base that had grown tired of Mr Trump and was concerned about his temperament for sitting in the Oval Office.

Multiple attendees wondered how the businessman could deal with Congress or Russian President Vladimir Putin if he couldn't handle a television presenter.

"Donald Trump made an unforced error," said Jay Salvi, who runs a machinery business in Miami, Florida. "He had a chance to apologise afterwards, and he did not. He showed he was not presidential material."

Republican rival Mike Huckabee urged people to turn their focus to issues

Myra Adams, a writer from Alexandria, Virginia, said that while she viewed Mr Trump as authentic, "in the presidential and political arena you have to play by some rules - diplomacy, respect, you have to just be able to have a filter."

Mr Trump, she said, doesn't have that filter.

"I thought Erick Erickson made a very bold, brave move and followed his convictions by disinviting him," she concluded.

Others in the crowd weren't so sure.

"They should have let him speak," said Frank Gorgie a professor from Nashville, Tennessee. "Just because he talks doesn't mean you agree with him. Do you think all the folks here agree with Chris Christie?" he asked, referring to the brash New Jersey governor who spoke on Friday morning.

Mr Gorgie also worried that the level of outrage directed at Mr Trump from the right may prompt the businessman to run as an independent in the general election, which could doom the eventual Republican candidate.

There was some dissenting opinion about the RedState move among conservative commentators as well.

Some conservatives are beginning to question Donald Trump's temperament

"I thought we were better than the leftist witch hunters," Jeff Goldstein of the conservative blog Protein Wisdom tweeted at Mr Erickson.

"Disinviting Trump merely reinforces the template the media will use to insulate Hillary. We've 'accepted' the left's 'misogyny' narrative," he added, referencing Democratic front-runner Hillary Clinton.

Even without setting foot in Atlanta, Mr Trump had turned the conference - and his party - upside-down with his latest bit of political performance art.

'Talk about issues'

The nine Republican candidates not named Trump continued their parade through the conservative confab, and given the opportunity, they all were pressed for their views on him.

On Saturday morning after his conference speech, former Arkansas Governor Mike Huckabee expressed frustration at the single-mindedness of the group of reporters surrounding him.

"Do we have another non-Trump question?" Mr Huckabee asked.

The next question, of course, was also about Mr Trump.

"I'm running for president, I'm not running for social media critic of someone else who's running for president," he snapped. "Talk to me about issues."

Jeb Bush is seeking to regain his frontrunner status amid the focus on Mr Trump

Former Florida Governor Jeb Bush - in an animated appearance that stood in sharp contrast to his sometimes somnambulant debate performance on Thursday - took aim at Mr Trump during his turn on the stage.

"Do we want to win? Do we want to insult 53% of voters?" he asked, adding that Mr Trump deserved to be disinvited and ought to apologise. Again the crowd cheered.

It seemed clear that Mr Trump had lost the RedState crowd. But does that mean he also lost the commanding lead he had in the latest round of public opinion polls? That will be revealed soon enough.

As he read off the nasty emails he had received on Saturday, Mr Erickson noted that he had gotten nearly a thousand, and more were pouring in. Mr Trump must have given out his email address, he said.

Nasty or not, those emails came from real people. And if there were thousands of them, there may still be a base of support out there that stands by Mr Trump, that sees the latest round of criticism, from the left and right, as proof that their man is rattling the powers that be - in Washington, at Fox News, in Atlanta, wherever.

If so, the Trump show is far from over.