Todd Akin, a candidate for U.S. Senate from Missouri, would like a do-over. Speaking about his opposition to abortion, which does not include exceptions for instances of rape, Akin issued an outrageous comment during a TV interview Sunday. Victims of “legitimate rape,” in Akin’s view, were far less likely to become pregnant.

In a week with little else going on in the political world, the issue exploded. From the president on down, Democrats lambasted Akin. Nervous Republicans concerned over what Akin’s continued candidacy would do to their chances of winning control of the Senate distanced themselves from the six-term member of the U.S. House. For his part, Akin has vowed to fight on in his bid to defeat Missouri incumbent Sen. Claire McCaskell.

The takeaway from this blowup has little to do with the Republicans vs. Democrats ground game. The bigger lesson is how democracies make policy and the methods employed to come to decisions.

In the case of abortion, Akin was like many of his fellow elected Republicans, including Paul Ryan, Mitt Romney’s pick for vice president. In this view, abortion is a moral wrong in all cases, including rape, incest or when the mother’s life is in danger. To justify this view, Akin relied on myth — the scientifically unsupported view that “legitimate” rape victims would not need an abortion because they would be less likely to conceive. “If it’s a legitimate rape, the female body has ways to try to shut that whole thing down,” Akin said over the weekend.

Unfortunately, this is not an isolated case of policy based on myth, quackery and superstition. Too often our public deliberations are polluted by half-truths and outright deceptions.

For example, there is no debate among the vast majority of climate scientists over whether the planet is warming. It is, according to the science at hand, and a main culprit is human activity.

Based on the evidence of recent prosecutions, voter fraud is not a widespread problem in the United States. Because in-person voter fraud is rare and a horribly inefficient method of rigging an election, requiring a photo ID at polling places is an unnecessary waste of time.

There’s not enough “waste, fraud and abuse” (to cite the politicians’ old saw) in the federal budget to cut in order to bring the federal books into balance. A bipartisan panel of experts has said the wisest course is a balanced mix of spending cuts and tax increases.

The nation has big decisions in front of it. Evidence and reason are needed now more than ever.