While Coburn's language would completely eliminate the subsidy, the pro-ethanol proposal would cut off the subsidy on July 1, and replace it with a variable subsidy that fluctuates with the price of oil. Proponents of the bill, like Sen. Richard Lugar (R-Ind.), said the variable subsidy bill would help guard against attempts by oil producers to lower the price of oil in order to drive the ethanol industry out of business.

"The proposal acts as a safety net to prevent OPEC from manipulating oil prices to kill off their ethanol rival," Lugar said. "When oil prices are high, as they are today, corn-based ethanol would not receive subsidy payments."

Under this proposal, ethanol blenders would get no subsidy at all when oil prices are above $90 a barrel. If oil falls to between $80 and $90 a barrel, they would get a six cents per gallon subsidy. Another six cents would be added for each $10 drop in the price of oil, and a maximum subsidy of 30 cents a gallon could be received when oil falls to $50 a barrel or less (a summary of the bill is here).

That's still less than the current 45 cents a gallon subsidy that ethanol blenders receive currently, regardless of the price of oil.

Proponents of the bill say ending the current system on July 1 and moving to a variable subsidy would save $2.5 billion. In a nod to Coburn and his supporters, the bill would use $1 billion of that for deficit reduction.

The rest would be used for the variable subsidy, but also for the development of ethanol infrastructure and other incentives. For example, the bill would expand tax credits to ethanol blender pumps, and extend through 2014 the small producer ethanol credit.

The bill is sponsored by Sen. John ThuneJohn ThuneCongress must address student loan debt crisis, a national economic drag Republicans go to battle over pre-existing conditions GOP frustrated by slow pace of Trump staffing MORE (R-SD), who said Monday that senators should oppose Coburn's attempt to immediately cut off all subsidies to ethanol without warning.

"What the amendment our colleagues are trying to get a vote on tomorrow would do is basically to say to this industry: Yes, we are going to take away this particular tax incentive, and we are going to do it right in the middle of the year," Thune said. "We are going to do it, and we do not like this industry -- which is probably what animates a lot of the opposition to this because if people look at the facts, if they look at the contribution that biofuels have made to our fuel supply in this country, it is significant."

"This bill would transition to a more sustainable model of support for renewable fuel production in America instead of pulling the rug out from under an industry, with 4 days' notice, that employs hundreds of thousands of people in this country, as well as provides an alternative to oil," said Sen. Amy KlobucharAmy KlobucharCruz: Jokes about me in Franken's book 'obnoxious' The Hill's 12:30 Report Dem senators accuse Trump of purposefully holding back information MORE (D-Minn.), another sponsor.

Other sponsors are Sens. Dan CoatsDan CoatsGOP frustrated by slow pace of Trump staffing Budowsky: GOP summer of scandal The Hill's 12:30 Report MORE (R-Ind.), Richard DurbinDick DurbinUncertainty builds in Washington over White House leaks Top Dem: Kushner reports a 'rumor at this point' Sunday shows: Homeland Security chief hits the circuit after Manchester attack MORE (D-Ill.), Al FrankenAl FrankenFranken explains why he made an exception to diss Cruz in his book Trump and Russia: A timeline on communications Overnight Energy: Trump energy nominees face Congress | OPEC to extend production cuts MORE (D-Minn.), Charles GrassleyChuck GrassleyDems plot recess offensive on ObamaCare The case for protecting America's intelligence agency whistleblowers Senate confirms Trump's first lower-court nominee MORE (R-Iowa), Tom HarkinTom HarkinDistance education: Tumultuous today and yesterday Grassley challenger no stranger to defying odds Clinton ally stands between Sanders and chairmanship dream MORE (D-Iowa), John HoevenJohn HoevenRepublicans go to battle over pre-existing conditions Overnight Healthcare: Divisions emerge in Senate over preexisting conditions GOP senators meet with insurer for input on ObamaCare repeal MORE (R-ND), Mike JohannsMike JohannsLobbying World To buy a Swiss company, ChemChina must pass through Washington Republican senator vows to block nominees over ObamaCare co-ops MORE (R-Neb.), Tim JohnsonTim JohnsonCourt ruling could be game changer for Dems in Nevada Bank lobbyists counting down to Shelby’s exit Former GOP senator endorses Clinton after Orlando shooting MORE (D-SD), Mark KirkMark KirkTaking the easy layup: Why brain cancer patients depend on it The Mideast-focused Senate letter we need to see The way forward on the Iran nuclear deal under President Trump MORE (R-Ill.), Claire McCaskillClaire McCaskillSanders, Democrats introduce minimum wage bill Mnuchin: WH won't double-count economic growth Technology's role in human trafficking cannot be ignored MORE (D-Mo.), Jerry MoranJerry MoranWeek ahead: Obama's CIA chief to testify on Russia probe IT modernization bill passes House Cost of key cyber bill drops by billions after revisions MORE (R-Kan.) and Ben Nelson (D-Neb.).