For decades, many presidential candidates campaigning in Iowa have made sure to offer their loud support for ethanol — the fuel made from corn.
Ethanol is an important industry in Iowa. The state is the top producer of ethanol in the nation, accounting for 28 percent of national production, according to the U.S. Energy Information Administration.
But this election cycle, ethanol is not the campaign force it once was.
Take the contrast between George W. Bush's 2000 presidential campaign and the current campaign of his brother, Jeb Bush.
During a 1999 debate in Iowa, George Bush declared: "I support ethanol, and I support ethanol strongly. I'd support ethanol whether I was in here in Iowa or not."
That position helped power Bush to victory in the 2000 Iowa caucuses before eventually winning the White House. The Bush administration created the Renewable Fuel Standard that required ethanol to be blended into the nation's gasoline supply. These days, the Obama administration is proposing to scale back the proposal.
Meanwhile, Jeb Bush, the former governor of Florida, has adopted a very different position from his brother on ethanol policy.
"I think, ultimately, we need to get to a point where there aren't winners or losers based on subsidies or mandates or anything else," Jeb Bush said in an interview with Iowa Public Radio.
That's a common response from Republican presidential candidates these days, and it comes at a time when the ethanol industry is struggling. New fuel-efficiency standards have lowered demand for gasoline — and ethanol — while some critics say the fuel's environmental benefits haven't panned out either.
The ethanol industry is trying to stay in the political debate by tracking what candidates are saying about the Renewable Fuel Standard and offering caucusgoers a report card on candidates' positions.
"We want to make certain that whoever is in the White House, whether it's a Democrat or Republican, that they understand this issue, that they support it," said Patty Judge, a former Iowa agriculture secretary and co-chair of America's Renewable Future, a bipartisan group funded by the biofuels industry. "Seventy-three thousand jobs in Iowa are in jeopardy if that Renewable Fuel standard should go away, and we just don't want to see that happen so we're going to be pushing pretty hard."
One reason presidential candidates aren't pandering to Iowa industries anymore is because the campaigns have become increasingly focused on national audiences rather than Iowans, argues Doug Gross, a prominent Iowa Republican.
"You're not going to Iowa and just talking about Iowa," Gross said. "You're going to Iowa and talking about the issues that are involved in your national narrative, because you're trying to drive your national poll numbers, so you can get on the national debate stage, so people can become aware of you."
It's just a question of whether Iowa issues — like ethanol — will still fuel that early stretch of road to the White House.