Senate Majority Whip John Cornyn said Friday at the CERAWeek energy conference in Houston that breakthrough is possible in the ethanol wars because both sides have reason to come to the table. The Texas Republican said he's trying to broker a compromise over the federal biofuels mandate, called the Renewable Fuel Standard, between interests from oil- and corn-producing states.

Why it matters: the RFS has long been the stuff of furious lobbying battles between different business interests. It pits the oil industry, which says the program is badly broken and unwieldy, against crop farming and ethanol interests that are influential in heartland states.

What's next: Cornyn, who represents a state with major oil refiners, said corn interests have reason to come to the table. That's because a 2007 law sets specific requirements for escalating amounts of various kinds of biofuels in the nation's fuel mix through 2022, but after that puts full authority over the levels in the hands of EPA regulators.

"It's in their interest to engage because after 2022 the mandate goes away and goes to the EPA administrator, and the EPA has been somewhat skeptical about ethanol and its viability long term," he said. Rep. John Shimkus, a senior member of the House Energy and Commerce Committee, is working on a parallel effort across the Capitol.