There were groans from the crowd over a mention of President Barack Obama’s new plan to combat climate change. Raucous cheers at a vow to frustrate House Speaker John Boehner. And jeers at the mention of the health care overhaul - and the sight of Republican candidates deemed too moderate.

The first Republican presidential debate unfolded in Cleveland Thursday as hundreds of partisans arrive in Atlanta for this weekend's RedState Gathering, and the crowd was eager to show its strain of hard-right conservatism at a pre-debate forum.

Several speakers mocked Obama’s foreign policy - one played a movie called “The World on Fire” that highlighted the Islamic State’s spread - and debated whether real estate developer Donald Trump will help pull the crowded field further to the right.

The crowd cheered loudest for Trump, Texas Sen. Ted Cruz and Wisconsin Gov. Scott Walker.

Former Florida Gov. Jeb Bush was booed during his introduction, and was greeted with cold silence amid his remarks that he was called “Veto Corleone” in his home state for his budget-slashing efforts.

He was booed again when he said he stood by his statement that there should be a way for illegal immigrants to earn legal status.

“People are dying because of the fact that local governments aren’t following the federal law,” Bush said, adding: “There should be a path to earn legal status here.”

A loud burst of applause came next when Trump, asked about his provocative comments about Mexico sending illegal immigrants across the border, blamed “stupid” American leaders.

“If it weren’t for me,” he told the panel, “you wouldn’t even be talking about illegal immigrants.”

The biggest outburst, though, took place when New Jersey Gov. Chris Christie traded barbs with Kentucky Sen. Rand Paul over strategies to combat terrorism. The crowd erupted into applause when Paul evoked Christie’s embrace of Obama after Superstorm Sandy rocked the Northeast in 2012.

The event, organized by WSB Radio host Erick Erickson, has put Atlanta in the presidential spotlight like never before. Erickson called it the largest gathering of presidential candidates in Georgia history (the huge field of candidates surely didn't hurt) and said that 186 credentialed reporters from more than a dozen countries will attend the event.

“The next president of the United States will be speaking this weekend,” said Erickson. “And for those of you who might be embedded liberal trolls, we did not invite Hillary Clinton.”