The America’s Renewable Future campaign is challenging the two confirmed Republican presidential candidates to take a stand for renewable fuels.

In a letter to Sen. Ted Cruz (R-TX), who has been forthcoming about his opposition to the Renewable Fuel Standard (RFS), ARF questioned his recent reported comment that the oil industry “doesn’t get subsidized.” The letter, with the message that “Oil Subsidies Are Real,” details $165 billion in subsidies and tax breaks the oil industry is poised to receive over the next ten years.

With Sen. Rand Paul (R-KY) officially declaring his candidacy this week, ARF recognized his introduction of the Fuel Choice and Deregulation Act as “a step in the right direction” but urged him to commit to supporting the Renewable Fuel Standard. “Sen. Paul has an opportunity to stand up for a commonsense, bipartisan policy that provides access to the marketplace for a clean, domestic alternative to foreign oil and we hope that he will,” said the campaign in a statement.

Another potential presidential candidate, Donald Trump, was in Iowa on Wednesday and took the time to meet with ARF co-chair Annette Sweeney “to discuss the importance of the ‪#‎RFS‬ to America and our rural communities.”

America’s Renewable Future is an Iowa-based coalition formed with the goal of educating presidential candidates about the RFS and urging their support.