It seems President Donald Trump’s administration made significant progress Wednesday toward appeasing a bloc of corn-state Republicans blocking EPA nominees over the agency’s actions on biofuels, but the small-yet-powerful group proved over the last two days that they have significant power to throw sands in the gears of the president’s agenda if they want. “We have enough of a bloc of Midwestern senators that they’re going to have to pay attention to us,” Sen. John Thune, a member of Senate leadership, told ME.

Key corn-staters seemed more optimistic of the directions of talks but weren’t ready to declare victory just yet. Sen. Joni Ernst, who held up a scheduled EPW vote Wednesday, said she wanted guarantees “either in writing or a public announcement” and her frustration level remains “pretty high” over the administration’s biofuels stance. “We want the president, we want the EPA administrator to be very public about the steps that they can announce in a meaningful manner,” she told reporters. “We want to know that [EPA Administrator] Scott Pruitt, as the head of the agency, is going to follow the spirit of the law. I have no doubt that they might try and follow the letter of the law but the spirit of the law is for energy independence here in the United States and to support the renewable industry in the United States.”

“I told them outright that I would not support [air nominee Bill Wehrum] if I didn’t have assurances," Ernst said. "I am the single Iowa Republican on that committee — 11 to 10. Eleven Republicans, 10 Democrats. One vote makes a difference.”

Iowa Republican Chuck Grassley said his concerns had "not yet" been satisfactorily addressed. And Sen. Deb Fischer, who indicated she’d vote in favor of Wehrum after meeting with Pruitt on Tuesday, told reporters: “I feel better, but I think more can be done.”

Pruitt spoke to Iowa Gov. Kim Reynolds Wednesday, a spokesman said. “What Administrator Pruitt said in his confirmation hearing still stands: he doesn’t want to take any steps to undermine the objectives in the statute of the RFS.”

White House officials asked EPA to stop back off plans to reduce advanced biofuel volumes and allow credits for exported ethanol, Pro’s Eric Wolff reports, citing multiple sources. "They had no choice," said one refining industry source who’d spoken to White House aides.

Meanwhile, the heads of four refiners at the heart of the skirmish — Valero, HollyFrontier, PBF and Monroe Energy — sent a letter to Trump Wednesday urging the administration to make biofuel exports eligible for credits, known as RINs. Pruitt has reportedly been considering such a move. “EPA has within its power the ability to level the playing field by treating exports the same as domestically-consumed products, removing a self-imposed trade barrier that unfairly discriminates against exports,” they wrote.