CNN "State of the Union" interviews during 2015: on Environment

Chris Christie: Ethanol in gasoline is the law; and that's just the minimum

Other contenders offered entirely opposite positions. New Jersey Gov. Chris Christie, for example, said he "absolutely" supports the RFS. "That's what the law requires. So let's make sure we comply with the law. That should be the minimum," he said, drawing applause from the crowd.

Jeb Bush: Let the market decide on RFS' ethanol in gasoline

Bush acknowledged that the mandate, which passed in 2007, has helped lower dependence on foreign oil and boost corn-heavy economies. "But as we move forward over the long haul, there should be certainty for people to invest," he argued, saying ethanol will no longer need help from the government. "So at some point we'll see a reduction of the RFS need, because ethanol will be such a valuable part of the energy feedstock for our country." He declined, however, to suggest when exactly that may happen.

Bush's frank statements on the RFS indicated that he plans on sticking with his positions, no matter how unpopular they may be to certain audiences.

Mike Huckabee: Ethanol mandate is a matter of national security

Huckabee, who won the Iowa caucuses in 2008, hit back at criticism that politicians like him simply support the RFS for political reasons: "The decisions are made not just frankly for what's best for Iowa--that's not the rationale. You can't make a decision and say, 'It's good for Iowa. Gee, they're the caucus state, we better suck up to them.' We better make decisions that are good for every consumer," he said.

Rick Perry: Ethanol waiver in Texas but not in Iowa: let states decide

Rick Santorum: Ethanol mandate brings jobs & energy independence

Rick Santorum, who won the Iowa caucuses in 2012, ticked off what he called a "laundry list" of benefits, including more energy independence and more jobs for farmers. "It is very important for rural Americans," said the former senator from Pennsylvania.

Scott Walker: Keep ethanol mandate until oil companies allow free market

But Walker said that his goal would be to get to a point where ethanol can compete openly and "you no longer need in the industry to have these subsidies."

Ethanol proponents argue that because oil companies own gas stations, consumers are unable to access ethanol and therefore it needs the government's support to break through oil's stronghold of the market.

Ted Cruz: Don't pick winners & losers like RFS' ethanol in gasoline

"I have every bit of faith that businesses can continue to compete and continue to do well without having to go on bended knee asking for subsidies, asking for special favors," he said. "I think that's how we got in this problem to begin win."

Ethanol proponents argue that because oil companies own gas stations, consumers are unable to access ethanol and therefore it needs the government's support to break through oil's stronghold of the market. Cruz acknowledged that his view wouldn't be well-received: "Look, I recognize that this is a gathering of a lot of folks who the answer you'd like me to give is, 'I'm for the RFS, darn it.' That'd be the easy thing to do. But I'll tell ya, people are pretty fed up, I think, with politicians that run around & tell one group one thing, tell another group another thing.