It is not encouraging that some candidates in the Republican presidential sweepstakes are using scientific knowledge as political footballs. Actually, not all scientific knowledge — just the kind they find uncomfortable or unpopular, which they blithely dismiss.

Addressing reporters at the Republican Leadership Conference in New Orleans in June, Michelle Bachmann, waving the banner of the tea party, declared that biological evolution was not science.

“I support intelligent design,” she said, reported CNN. “What I support is putting all science on the table and then letting students decide.”

Of course, that’s exactly what public education in biology has been doing, year in, year out: putting science, and only science, on the science table.

Biological evolution is on the table because it is science, based on centuries of repeated observation, experiment and discovery. Intelligent design, a gussied-up version of creationism, is off the table because it is based on Genesis. The lesson for students is immediate: Intelligent design cannot pose as science because it invokes the supernatural to explain natural phenomena, in this case, the history and diversity of life on Earth.

For the same reason, we don’t place the stork theory of sex on the table alongside reproductive biology for students to choose. Or a flat Earth beside a round Earth. Or a sun-centered solar system opposite an Earth-centered one. Or an Earth that is 6,000 years old versus one that is 4.5 billion years old, despite the fact that there are factions out there who believe, in the face of facts, that the Earth is flat, 6,000 years old and at the center of our solar system.

Rep. Bachmann went on to say, “I don’t think it’s a good idea for government to come down on one side of a scientific issue or another, when there is doubt on both sides.” Right, except there is no doubt on either side. Science has no doubts about biological evolution. And faith has no doubts about a supernatural deity. One explains the heavens, the other how to get to heaven, to paraphrase Cardinal Baronius’ 1598 quip. Neither governments nor anyone else should mix or confuse the two.

It’s fine if Rep. Bachmann finds biological evolution personally uncomfortable. But discomfort should not trump knowledge or a responsible science education for the nation’s students, particularly if the U.S. is to remain competitive in a global economy that is overwhelmingly scientific and technological. And knowledge of evolution is an economic necessity. It underpins U.S. and global R&D on the production of the world’s food, fiber, fuel and pharmaceuticals.

Meanwhile, former U.S. Sen. Rick Santorum is busily kicking global warming toward his goal of Republican nomination. On Rush Limbaugh’s radio show in June he labeled global warming “junk science,” stating “the idea that man, through the production of CO2 … is somehow responsible for climate change is, I think, just patently absurd.” On June 25, he told Fox News’ Glenn Beck, “There is no such thing as global warming.”

Well, here too there is no doubt. Science has no doubt that rapid global warming has occurred during the past hundred years, much of it due to greenhouse gases from human industrial activity. Judging by ExxonMobile and its CEO, Rex Tillerson, the energy sector has no doubt that “our climate is changing, the average temperature of the earth is rising, and greenhouse gas emissions are increasing … [which] … pose significant risks to society and ecosystems.”

The insurance sector agrees. Swiss Re, one of the world’s major insurers, warns that “Climate change will significantly affect the health of humans and ecosystems and these impacts will have economic consequences.” Marsh and McLennan, the world’s largest insurance broker, recently issued a “risk alert” to clients, saying “Climate change — often referred to as ‘global warming’ — is one of the most significant emerging risks facing the world today, presenting tremendous challenges to the environment, to the world economy, and to individual businesses.”

Corporations know that data do not lie or deny. They abide by the current parable that people are entitled to their own beliefs, but not their own facts. They respect mathematical analyses of a century of rising temperatures, dramatic increases in concentrations of CO2 (36 percent) and methane (148 percent) since 1750, rapidly shrinking glaciers on sea and land, and increasing acidification of the world’s oceans.

The Economist, a mainstream conservative business magazine, asks the simple question: “How frightened should people be about this” remaking of the planet? Their answer: “It would be odd not to be worried.”

Bachmann and Santorum, apparently, are not worried, comforted in the belief that most scientists in the U.S. and worldwide are either incompetent or liars or both. They also appear to believe that their categorical rejection of unpopular knowledge is somehow a litmus test for Republican presidential aspirants.

A truer litmus test, ironically, is just the opposite. Leadership requires the honest grit to deploy the best knowledge, no matter how uncomfortable or unpopular, in making the tough, critical decisions demanded of presidents.