Ted Cruz has dared to provoke the ire one of the most ruthless and vengeful political forces on the planet, and it’s not Donald Trump. The Texas senator has crossed the ethanol industry in Iowa, which is a little like getting on the wrong side of the Catholic Church in Vatican City.

Cruz’s core theme is fighting the “Washington cartel,” which would be a lot easier if its tentacles didn’t extend all the way into the state crucial to Cruz’s presidential hopes.

Other Republicans have refused to bow and scrape before the ethanol industry — John McCain wouldn’t do it 2000, but he didn’t compete in Iowa. Cruz, in contrast, has staked an enormous amount there. His campaign could have been engineered in a lab for Iowa: He is an evangelical who is a hard-liner on immigration and has organized relentlessly on the ground. The only dissonant note is his opposition to the so-called Renewable Fuel Standard that is a government prop for the industry. Cruz’s stand against it is an act of reckless courage.

The Renewable Fuel Standard requires that ethanol is blended into the nation’s gasoline, and in ever-increasing amounts. The mandate increases the price of gas while doing nothing for the environment. Even former boosters like Al Gore have given up on ethanol as a green wonder fuel. It does much less than advertised to reduce carbon emissions once the entire process of producing it is taken into account.

The economic and environmental effects are beside the point, though. Ethanol gobbles up 40 percent of the corn supply, and so the mandate is beloved by agricultural interests. Iowa is the nation’s top corn-producing state and has a political trump card. To paraphrase the Paul Harvey Super Bowl ad from a couple of years back, the ethanol mandate can’t survive on the merits, “So God created the Iowa caucuses.”

Possession of the first contest on the presidential-nomination calendar gives Iowa unparalleled power to make presidential candidates prostitute themselves to King Corn. Almost all of them are happy to do it, except for Ted Cruz, who insists — and this is radical for Iowa — that the mandate be phased out in 2022, or midway through his prospective second term.

The ethanol machine, under the auspices of America’s Renewable Future, has done everything to dog Cruz short of declaring him wanted for grave offenses against Iowa’s favorite boondoggle. The group is headed by Eric Branstad, whose dad happens to be Iowa’s governor for life, Terry Branstad, now on his sixth term. Gov. Branstad recently baldly stated that he wants Cruz defeated. This is a little like the papal bull issued against Queen Elizabeth in 1570 excommunicating her from the Catholic Church and implicitly sanctioning attempts on her life. Branstad wants Cruz dead, and doesn’t particularly care who does the deed.

Enter Donald Trump, the political neophyte and alleged outsider who has a career politician’s instinct for the shameless and self-abasing pander. Trump has done everything but drink pints of ethanol on the stump and promise to open up his own beautiful, gold-plated, Trump-branded ethanol production plants. For Trump, there is nothing wrong with the ethanol mandate that can’t be cured by making it bigger and better. Trump is supposed to be the fearless truth-teller and a disruptor of the political system, but he is fearlessly telling people what they want to hear and promising to protect a cozy special-interest arrangement.

On ethanol, it is Cruz who is a threat to the status quo. Ethanol’s political hold has been slipping. A tax credit for the industry and a tariff protecting it ended a few years ago. Now, it is faced with the prospect of a candidate who could win the Iowa caucuses while defying King Corn. If the proponents of ethanol have their way — to borrow from a phrase associated with the oil industry they so hate — there will be blood.

Rich Lowry can be reached via e-mail: comments.lowry@nationalreview.com.