The Iowa Freedom Summit was unofficially billed as the kickoff to the 2016 Republican presidential campaign. Nearly every candidate who is considered to have a realistic shot at the nomination showed up to varying levels of enthusiasm from the crowd.

The first speaker to make a real splash was Dr. Ben Carson, who brought the crowd to its feet several times

Carson, the first of many potential White House contenders to speak, walked the audience through his humble beginnings as he casually paced the stage. The former Johns Hopkins University pediatric neurosurgeon earned nods and laughter as he talked about growing up poor in Detroit and the sacrifices his mom made to help him succeed.

Carson then pivoted to red-meat, using a a soft-spoken and folksy style that belied some of his rhetoric to blast ObamaCare and attack illegal immigration.

Carson has polled well in early-caucus Iowa, and local strategists say he shouldn't be dismissed as a potential player. His speech showed why.

"I don't believe in taking the most important thing a person has, which is their health, and putting it in the hands of the government," he said to strong murmers of approval.

"Do we have an illegal immigration problem?" he asked a minute later, as the crowd yelled back "yes."

"Can we fix it?"

"Yes!" the crowd roared.

"Of course we can," he said. "There wouldn't be people coming here if there wasn't a magnet... you have to reverse the polarity of that magnet."

Other presidential wannabes who spoke included Mike Huckabee, Ted Cruz,  Rick Perry, Rick Santorum, and Ambassador John Bolton.

Significant abesentees included Rand Paul, Jeb Bush, and Mitt Romney. Bush and Romney were the preferred targets of some speakers, Donald Trump in particilar:

His aides passed out photos of Trump shaking hands with Ronald Reagan as quickly as Trump himself tossed off insults. He said Mitt Romney "choked" in 2012, and that "the last thing the country needs is another Bush."

"You just can't have those two," Trump said to cheers, referencing the men whose last names have adorned all but two GOP presidential tickets since 1980. Both Romney and Bush skipped the gathering in Iowa, which drew a dozen others -- including Trump -- who are considering candidacies.

Other speakers railed against the establishment. Sarah Palin:

Sarah Palin made the trip, fresh off of telling ABC News earlier this week that "of course" she's interested in running in 2016, too.

The former Alaska governor weaved through a speech hitting predictable subjects like Hollywood liberals, the mainstream media, and Hillary Clinton to train some fire on "RINOs" -- Republicans in name only -- whom she said want "amnesty" for undocumented immigrants.

She praised the event's main host, Rep. Steve King, for being "one of the brave, one of the few, to actually pull the lever" and oppose House Speaker John Boehner in an ill-fated and barely planned coup attempt earlier this month.

Talking about the upcoming GOP race, she paraphrased Ronald Reagan, in a line often used by Sen. Ted Cruz as well.

"Now is the time for bold conservative colors, not establishment pale pastels," Palin said. "I am not in the mood to give politicians a pass just because they have a certain party initial next to their name."

Perhaps the most surprising turn at the podium was when Scott Walker wowed the crowd with an impassioned speech that mixed his personal life story with his success in passing conservative policies.

Wisconsin Gov. Scott Walker (R) delivered a fiery speech in Iowa on Saturday, wowing the conservative crowd with a passionate argument for small government and his own lengthy resume.

The Wisconsin governor, in rolled-up shirtsleeves, paced the stage as he blasted big government and touted a long list of conservative reforms he's pushed through in blue Wisconsin.

The governor also showed a rhetorical flourish that's largely been absent from his previous campaigns, drawing the crowd to its feet multiple times.

"There's a reason we take a day off to celebrate the 4th of July and not the 15th of April," he said, almost yelling as his voice grew hoarse. "Because in America we value our independence from the government, not our dependence on it."

Walker's speech had something for every element of the activist crowd. The governor touted his three victories over Democrats and recall win as well as his state-level education reforms. Each new policy he helped pass drew cheers: Voter ID laws, education reforms, tax cuts and defunding Planned Parenthood.

The biggest question for Walker as he ramps up for a race is whether he has the fire in the belly and political skills to stand onstage against the other candidates. And in his first major Iowa address, he may have done a lot to dispel notions that he lacks charisma.

When he said he won reelection as Milwaukee County Executive in an area where President Obama won by a two-to-one margin, some in the audience gasped.

"If you get the job done the voters will actually stand up with you," he said before contrasting his record with Washington's deadlock.

With 53 weeks to go before the Iowa caucuses, nobody won or lost the nomination at this event. But as a way to showcase what even some Democrats are saying is the deepest GOP field in memory, and raise the profile of some candidates, it was a huge success.