NEVADA, Iowa | Gov. Terry Branstad gave some Hawkeye State advice to presidential aspirants Friday: support ethanol.

“If they want to have a chance in Iowa, they better embrace it, and they better join us,” he said. “I mean this is pretty loud and clear.”

Branstad said ethanol wasn’t a big issue in the last election because of fluctuations in the price of corn.

“People say, ‘Well, ethanol wasn’t a big issue in the last election.’ Well, yeah the price of corn was sky high,” Branstad said after an event at Lincolnway Energy in rural Nevada to rally support for a higher Renewable Fuel Standard. “Well, now, it’s down to the cost of production, and the EPA is trying to reduce the RFS. It is going to be a huge issue.”

The RFS is the federally mandated Renewable Fuel Standard that requires a certain amount of biofuels in the national transportation fuel supply.

Proposed rules from the Environmental Protection Agency released last week cut the amount of required renewable fuels that would be required in coming years.

“He (Branstad) would deny that’s a threat, of course,” Drake University Politics Professor Dennis Goldford said. “But the governor vehemently represents what is an interest group.”

That interest group is the agriculture industry, which benefits from the guaranteed market created by the Renewable Fuel Standard. Iowa ethanol and biodiesel manufacturers produce billions of gallons a year.

Iowa, because of its first-in-the-nation presidential caucuses, is a key launching point for presidential campaigns. Doing well in the Hawkeye state can bring notice and otherwise unattainable media coverage to a candidate, making it important for candidates to curry favor with Iowa interest groups.

Or so the thinking goes.

“The leverage (Branstad) has is ‘you won’t do well in the caucuses if you don’t endorse ethanol,'” Goldford said. “I don’t know if that’s the case. Maybe it is, but I haven’t seen evidence of it. It might be a make-or-break issue for some, but it’s not one of those broad-based issues.”

For instance, Goldford asked rhetorically, would a rural Iowa Republican caucus-goer vote for a Democrat if the Democrat was a bigger supporter of ethanol than the GOP candidate?

“I think that’s hard to say with certainty,” he said.

Branstad said Friday that by proposing to reduce next year the amount of ethanol blended into gasoline, environmental officials had "embarked on a war on corn." He said EPA Administrator Gina McCarthy indicated in August during a visit to Iowa she favored maintaining the ethanol volume requirements.

But Branstad added, "They still went ahead and proposed a bad rule. It's unbelievable the EPA embarked on a war on corn. It makes no sense," he said.

Branstad said ethanol production is key to maintaining a strong economy in Iowa, the nation's leading corn producer and top ethanol maker.

Branstad was accompanied at Lincolnway Energy near Nevada by U.S. Senator Chuck Grassley, U.S. Rep. Steve King and Iowa Secretary of Agriculture Bill Northey.

They spoke to about 150 farmers, ethanol industry workers and others who gathered in an unheated metal building with temperatures hovering just above 20 degrees.

Grassley said a good turnout should show ethanol opponents the tenacity of Iowa farmers.

"Right now you don't have pitchforks, but you're ready to fight for this issue," he said.

King said he plans to read very carefully the law that established the Renewable Fuels Standard to see under what circumstances the EPA is allowed to lower it and to see whether to filing a lawsuit is an option.

-- The Associated Press contributed to this story.