I could see it coming.

During Sen. Marco Rubio's speech in Iowa over the weekend, celebrating Gov. Terry Branstad's Birthday Fundraiser, the GOP's rising star mentioned the 6,000 years of recorded human history.

He had used similar lines in his stump speech before, saying, for example, that socialism "hasn't worked in 6,000 years of recorded history." But now, he was on center stage, auditioning for a future presidential campaign. And something told me liberal secularists would pounce.

It didn't take long. 

During an interview with GQ, Rubio was asked, "How old do you think the Earth is?" (In fairness, all I know about the timing of the interview is that it was "recent," meaning it potentially happened before the Iowa speech.)

Rubio's hemming-and-hawing answer, which included lines like "I'm not a scientist, man," drew predictable mockery. And of course, the reason this issue potentially hurts Rubio is that it plays into a larger narrative that Christian conservatives are anti-science. Rubio, as a rising GOP star with national ambitions, must simultaneously remain acceptable to tea party conservatives, who will surely be influential in the 2016 primaries, and beyond, while also being taken seriously by the mainstream media.

Consider 2008: During a GOP presidential debate, the candidates were asked to raise their hands if they did not believe in evolution. It was a silly exercise. But in retrospect, John McCain's response was a smart and nuanced one: "I believe in evolution," he said. "But I also believe, when I hike the Grand Canyon and see it at sunset, that the hand of God is there also."

You can believe in the Divinity of Christ and also believe that the Earth is billions of years old.

McCain was voicing an argument that is gaining steam — the notion that one can be a Christian who believes in the Divinity of Christ, but also that the Earth is billions of years old.

In general, Catholics have been open to the notion that there is no contradiction between evolution and faith, with Pope John Paul II going out of his way to reaffirm this in 1996. (Rubio — a Catholic who grew up a Mormon and sometimes attends evangelical churches with his family — has surely heard all the theories.) Protestants generally took an opposing view. But even that is starting to change.

During a recent panel discussion, Tim Keller, who pastors New York City's Redeemer Church, said, "[T]he Bible does not teach that the Earth is young." Keller went on to explain that "the genealogies are not complete." (By this he means that Bible verses stating "so and so begat so and so" imply ancestry, not specifically fatherhood.) Ultimately, Keller concluded that a belief in (or against) an old Earth shouldn't be a deal-breaker for salvation. "[It's] not in the Apostle's Creed," he explained, "and therefore there's wiggle room."

Interestingly, although this debate over evolution and the Earth's age has invaded our politics for almost a century, prior to the era of William Jennings Bryan and the Scopes Monkey trial, many Protestant Christian theologians thought evolution was acceptable as part of God's plan.

In his 1908 classic book Orthodoxy, the Roman Catholic convert G.K. Chesterton observed, "If evolution simply means that a positive thing called an ape turned very slowly into a positive thing called a man, then it is stingless for the most orthodox; for a personal God might just as well do things slowly as quickly, especially if, like the Christian God, he were outside time."

Indeed, as Baylor professor Barry Hankins told me in a recent podcast interview: "[S]ome of the best conservative, evangelical theologians of the late 19th century were willing to consider ways in which evolution — not Darwinism or Darwin's theory of how evolution took place — but evolution, itself, could be part of God's plan. But by the 1920s, the categories had hardened."

After I posted that, a reader later sent me this citation from B.B. Warfield's A Biblical Inerrantist as Evolutionist:

"Benjamin Breckenridge Warfield of Princeton Theological Seminary, the theologian who more than any other defined modern biblical inerrancy, was throughout his life open to the possibility of evolution and at some points an advocate of the theory."

So where does that leave us? 

The storm surrounding Rubio's comments speaks to a larger issue: The Republican Party and the conservative movement need to be more introspective. Conservatives need to think through their responses to these type of questions before they are asked. This is a discussion that conservative politicians of faith need to have; but I suspect, like talking to your kids about sex, it is generally avoided.

I can respect anyone's faith, and so I respect people who believe in a young Earth. But Christians and conservatives ought to know that science and God do not have to be at odds. 

When I said the GOP needed to "evolve," this wasn't what I meant…