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 Randolph ThuneGOP struggles to find backup plan for avoiding debt default GOP frets over nightmare scenario for Senate primaries High anxiety hits Senate over raising debt ceiling 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 Jean KlobucharThe Hill's Morning Report - Presented by JUUL Labs - House to vote to condemn Trump tweet Fundraising numbers highlight growing divide in 2020 race Critics slam billion Facebook fine as weak MORE (D-Minn.), another sponsor.

Other sponsors are Sens. Dan CoatsDaniel (Dan) Ray CoatsThe Hill's Morning Report - Presented by JUUL Labs - Trump attack on progressive Dems draws sharp rebuke A brief timeline of Trump's clashes with intelligence director Dan Coats Chuck Todd on administration vacancies: 'Is this any way to run a government?' MORE (R-Ind.), Richard DurbinRichard (Dick) Joseph DurbinDurbin slams McConnell as Trump's 'greatest enabler' Problem Solvers Caucus co-chair calls Trump comments about progressive congresswomen 'totally unacceptable' Trump's tweets unify a fractured Democratic Party MORE (D-Ill.), Al FrankenAlan (Al) Stuart FrankenAl Franken: It's time to start taking Trump 'literally' The Hill's 12:30 Report: Mexican officials scramble to avoid Trump tariffs The Hill's Morning Report - Tariff battle looms as Trump jabs 'foolish' Senate GOP MORE (D-Minn.), Charles GrassleyCharles (Chuck) Ernest GrassleyThe peculiar priorities of Adam Schiff Advocates frustrated over pace of drug price reform Trump drug pricing setbacks put pressure on Congress MORE (R-Iowa), Tom HarkinThomas (Tom) Richard HarkinWisconsin lawmaker gets buzz-cut after vowing not to cut hair until sign language bill passed Democratic debates kick off Iowa summer sprint Key endorsements: A who's who in early states MORE (D-Iowa), John HoevenJohn Henry HoevenMcConnell ups pressure on White House to get a budget deal Senators introduce bill to prevent border agency from selling personal data Overnight Energy: Bipartisan Senate group seeks more funding for carbon capture technology | Dems want documents on Interior pick's lobbying work | Officials push to produce more electric vehicle batteries in US MORE (R-ND), Mike JohannsMichael (Mike) Owen JohannsMeet the Democratic sleeper candidate gunning for Senate in Nebraska Farmers, tax incentives can ease the pain of a smaller farm bill Lobbying World MORE (R-Neb.), Tim JohnsonTimothy (Tim) Peter JohnsonSeveral hurt when truck runs into minimum wage protesters in Michigan Senate GOP rejects Trump’s call to go big on gun legislation Court ruling could be game changer for Dems in Nevada MORE (D-SD), Mark KirkMark Steven KirkAdvocates push for EpiPens on flights after college student's mid-flight allergic reaction Funding the fight against polio Ex-GOP Sen. Kirk registers to lobby MORE (R-Ill.), Claire McCaskillClaire Conner McCaskillTrump nominees meet fiercest opposition from Warren, Sanders, Gillibrand Feds allow campaigns to accept discounted cybersecurity services GOP frets over nightmare scenario for Senate primaries MORE (D-Mo.), Jerry MoranGerald (Jerry) MoranBottom Line Senate GOP raises concerns about White House stopgap plan to avoid shutdown Trade truce puts focus on next steps in US-China talks MORE (R-Kan.) and Ben Nelson (D-Neb.).