It’s also the first big multi-contender GOP presidential forum that will attract business Republicans who are more interested in economic issues than social issues or God’s place in the civic arena.

A crush of national media will be in Des Moines to cover the ag summit, which will audition a dozen GOP presidential contenders over a seven-hour period in front of a sold-out audience of 900.

“I think it’s a brilliant idea to have this ag summit,” Gov. Terry Branstad told Iowa reporters Monday morning at his weekly news conference. “I think it’s a great opportunity for the candidates to really express their views on renewable fuels, on international trade, on regulations like waters of the U.S. and many other issues, regulatory and tax issues, energy issues affecting agriculture.”

The assemblage of potential presidential candidates will be bigger than Iowa’s previous cattle-call forums, including Bob Vander Plaats’ Family Leadership Summit in August, which attracted religious conservatives, and Steve King’s Iowa Freedom Summit, a January event that also drew heavily from the Christian conservative and tea party factions of the GOP.

Another key difference at this event will be the format. Rather than giving speeches, each contender will do a 20-minute question-and-answer session with host Bruce Rastetter, an agribusiness leader and GOP power player with close ties to Branstad.

1. Who are the hottest speakers?

All eyes will be on Wisconsin Gov. Scott Walker and former Florida Gov. Jeb Bush.

“Scott Walker is the runaway front-runner right now (in Iowa), so by default has the most to lose,” said Tim Albrecht, an Iowa Republican operative who will likely support Bush if he runs for president.

Walker, in January on his first foray into Iowa as an acknowledged presidential contender, rolled up his shirt sleeves, connected with everyday Iowans by talking about using coupons at Kohl’s, and scored points with conservatives by playing up his resolve on controversial reforms despite death threats to his family. The Iowa Freedom Summit speech marks the spot where Walker launched himself as a figure to be reckoned with in the 2016 race.

Now it’s Bush’s turn to make his first Iowa trip of the 2016 election cycle, while knowing that he’s viewed with wariness by conservatives here. Some people in the audience booed when New York businessman Donald Trump mentioned Bush’s name at the Freedom Summit.

Iowans know fewer details about Bush, who left the governor’s office in far-away Florida eight years ago and hasn’t visited here since October 2012, than they do about Walker, who has been making headlines in neighboring Wisconsin for four years and has ventured down for visits, Iowa Republicans said.

“When people think of Scott Walker, they think of one of precious few real conservative victories in the last decade,” said Joel Kurtinitis, a blogger and activist who considers himself a conservatarian — a conservative libertarian. “When they think of Jeb Bush, family ties aside, the first image that comes to mind is of him handing an award to Hillary Clinton.”

That’s a reference to praise Bush gave Clinton in 2013 when she won an award from the National Constitution Center for her international work on behalf of women and children. Bush was chairman of the group’s board of trustees at the time.

As for Bush, GOP politics watchers said they’ll be looking to see if he can chip away at the narrative that Iowa will be a real problem for him.

2. Who will exhibit the best farm savvy?

Former Texas Gov. Rick Perry might have the only claim on “farmer” status among the potential 2016 contenders. Although he no longer actively farms, he and his dad grew cotton. Perry studied animal science at Texas A&M, served as ag commissioner of Texas, and can still talk comfortably about breeding cattle for proper calf weights so births don’t stress the cows.

Conversely, mangling farm lingo can be quicksand for a presidential hopeful, Iowa Republicans said. This event will interject a new series of complex issues — genetically modified organisms, exports, biofuels, food security — into the debate over who’s best suited to be the next president.

When Democratic U.S. Sen. Ted Kennedy of Massachusetts decided to take on a fellow Democrat, President Jimmy Carter, in the 1980 Iowa caucuses, Kennedy gave a speech at Hancher Auditorium in Iowa City, recalls James Kersten, a former state senator from Fort Dodge.

“The speech was outstanding,” Kersten said. “But then during his stops across Iowa, he really showed he did not have an understanding of ag policy when asked by the press and voters. I think that lack of knowledge really hurt him.”

3. Will anyone be perceived as anti-ag?

Ethanol doesn’t have the political punch in the GOP caucuses that it once did, or it wouldn’t need a multimillion-dollar campaign that’s being rolled out to promote it, one Iowa Republican strategist said. But some heavyweight opinion leaders on both sides of the aisle in Iowa are cheerleading for the Renewable Fuel Standard, which guarantees market access for ethanol and biodiesel, despite Big Oil’s efforts to box out the industry, they say.

Texas U.S. Sen. Ted Cruz is vocally opposed to the Renewable Fuel Standard, a stance that appeals to tea party and liberty movement insurgents who want to eliminate government interference in markets.

Walker has dodged spelling out his views on the fuel standard in recent months. In a 2006 gubernatorial debate, he said ethanol mandates were “just fundamentally wrong,” according to the Wisconsin Journal Sentinel.

Trump has spoken out against wind energy.

Republicans said they’ll be listening carefully to see if all the contenders fully understand Iowa ag interests — and whether they pay homage to the RFS.

4. How will Christie deal with any awkwardness with the moderator?

The interplay on stage between New Jersey Gov. Chris Christie and moderator Bruce Rastetter could be interesting, Iowa Republicans said. Will Christie poke Rastetter a bit by saying he’s exactly the same guy that Rastetter 31/2 years ago thought would make such a great president?

But don’t expect any sharp elbows. The two men remain friendly and share an aide: GOP strategist Jeff Boeyink is an adviser to Christie and is one of Rastetter’s lobbyists.

5. Will Rubio be a new stand-out? Or someone else?

Iowa Republicans said they’re trying to figure out whether Florida U.S. Sen. Marco Rubio has an opening in Iowa, assuming he runs. Perhaps this appearance will offer some clues, activists said.

Some think this could be a chance to shine for Rick Santorum, a former Pennsylvania U.S. senator and strong supporter of the Renewable Fuel Standard. He won the 2012 Iowa caucuses, but has ranked in the back of the pack in recent polling. He’s fighting for some of the same religious conservative voters as the 2008 Iowa caucuses winner, former Arkansas Gov. Mike Huckabee.

“Rick is working to fight his way out of Mike Huckabee’s shadow, and this ag summit might be his chance to sell ag-first Iowans on his blue-collar conservatism model,” Kurtinitis said.

6. How will Patty Judge be received?

Iowa Democrats said they haven’t forgotten what Rastetter has done to try to demolish Democratic candidates by bankrolling GOP campaigns and organizations such as the American Future Fund, which in 2010 almost toppled Democratic U.S. Rep. Bruce Braley by throwing so much TV ad money against him.

Rastetter has been a thorn in the side of Iowa liberals and progressives when it comes to large-scale hog confinements and corporate farming. And they don’t like how he’s reshaping Iowa’s Board of Regents universities, they said.

None of the Democratic potential presidential candidates — Vice President Joe Biden, former U.S. Secretary of State Hillary Clinton, New York Gov. Andrew Cuomo, Minnesota U.S. Sen. Amy Klobuchar, former Maryland Gov. Martin O’Malley, Massachusetts U.S. Sen. Elizabeth Warren, former Virginia U.S. Sen. Jim Webb — accepted Rastetter’s invitation. Nor did Vermont U.S. Sen. Bernie Sanders, an independent.

It opened Clinton to GOP criticism that she’s out of step with agriculture and that she has written off Midwest states in her presidential campaign strategy, but Iowa Democratics dismissed that thinking.

U.S. Rep. Dave Loebsack’s campaign manager, Nick Clarksen, called the summit a highly partisan event and said only Republicans “will take this opportunity to kiss the ring of one of Iowa’s biggest money men.”

One lone Democrat will speak, former Iowa Agriculture Secretary Patty Judge. She has owned a cow-calf farm with her husband and is co-chair of America’s Renewable Future.

“Most everybody that will be there I disagree with on most every subject,” said Judge, who isn’t running for president. “But I really believe in the issue of renewable fuels. We’ve worked so hard to build this industry here. It’s producing good jobs and lessening our dependence on fossil fuels.”

This crowd is likely to be more respectful and less boisterous than some activist audiences, but whether they give Judge a warm reception is another question.

7. Will this event elevate Rastetter’s stature among Republicans?

Being in a daylong, nationally televised spotlight as the moderator will put Rastetter in some rarified air, but Iowa GOP activists said his standing will depend partly on how substantive he is. Will he lob friendly softballs or dig in on each of the contenders’ perceived vulnerabilities with the Iowa caucus electorate?

For example, will he grill Rubio on immigration reform, which is an important issue in some aspects of agriculture? Will he press Bush on education reform, given that Rastetter is head of the board that governs Iowa’s public universities?

GOP operative Robert Haus predicted: A stand-out performance could put Rastetter in the discussion for the governor’s race in 2018.

8. Will GOP contenders who skip the summit be hurt by their absence?

Kentucky U.S. Sen. Rand Paul, former Hewlett-Packard CEO Carly Fiorina and former physician Ben Carson will miss a chance to share their vision on U.S. agriculture and food production and how it relates to international trade and security.

But with so many names floating around in the bingo hopper, Iowans might not remember a few weeks from now who didn’t show up, GOP activists said.

Staff writer Brianne Pfannenstiel contributed to this report.

ABOUT THE IOWA AGRICULTURE SUMMIT

MODERATOR: Bruce Rastetter, an agribusiness leader and GOP power player, will do a 20-minute question-and-answer session with each potential presidential candidate who takes the stage.

DETAILS: Doors open Saturday at 7:30 a.m. at the Elwell Family Food Center at the Iowa State Fairgrounds in Des Moines. It will run until about 3:30 p.m.

SPEAKERS’ LIST: Potential presidential candidates who will speak are Jeb Bush, Chris Christie, Ted Cruz, Jim Gilmore, Lindsey Graham, Mike Huckabee, George Pataki, Rick Perry, Marco Rubio, Rick Santorum, Donald Trump and Scott Walker. All are Republicans. All the Democratic contenders declined the invitation. Prominent Iowa political and agriculture leaders also will speak.

TICKETS: All of the tickets, which were free, have been reserved. A crowd of about 900 is expected.