In the run-up to Glenn Beck’s religious-themed rally at the Lincoln Memorial Saturday, Rep. John Fleming, R.-La., issued a stark warning about the voters’ choice in November. Either we “remain a Christian nation,” he told a GOP women’s group last week, or it’s “down the socialist road” to “a godless society.”

Standing by was Fleming’s fellow Louisiana Republican, Sen. David Vitter, the most famous “john” in 2007’s “D.C. Madam” scandal. Awkward.

The GOP has lately drawn energy from the Tea Party movement, which sprung up in 2009 to protest overweening government. That’s where the TP’ers kept the focus early on, sensibly calling a truce on “culture war” issues.

Unfortunately, judging by the rise of “Christian nation” rhetoric among Tea Party figures, that’s starting to change.

In April, Sarah Palin told the evangelical group “Women of Joy”: “Lest anyone try to convince you that God should be separated from the state, our founding fathers, they were believers.”

They were — but so what? Those believers deliberately crafted “A Godless Constitution.” In their 1996 book by that name, scholars Isaac Kramnick and R. Laurence Moore chronicle our proud heritage of secular government, in which, as Madison put it in his Memorial and Remonstrance, religious beliefs are “not the object of civil government, nor under its jurisdiction.”

The Constitution’s early critics complained “that it was indifferent to Christianity.” The Rev. Timothy Dwight, president of Yale, thought we were losing the War of 1812 because we had “offended Providence,” having “formed our Constitution without any acknowledgment of God.”

Indeed, Kramnick and Moore write, the Framers enshrined “the Lockean liberal ideal” in the nation’s fundamental law, creating “a demystified state, stripped of all religious ambitions.”

Today, some Americans apparently fret about whether President Obama is “really” a Christian. Well, he sure sounds like one, as when he complained last summer about “folks who are frankly bearing false witness” about his health care bill, or when, on the campaign trail, he told one church gathering that, with the right leadership, “we can create a Kingdom right here on Earth.”

Whatever happened to that “demystified state”?

I headed to the Beck rally Saturday, seeking fodder for a “What I Saw at the Revolution” column. But what I saw wasn’t all that revolutionary.

Amid the usual Gadsden (“Don’t Tread on Me”) banners were a few “Christian flags” — white, with a red cross in a blue canton. Mostly gone were the spunky anti-government signs that dominated earlier rallies (organizers had discouraged them). Overall, it was largely as Beck had promised: 8/28 had “nothing to do with politics” and “everything to do with God.”

The God Preacher Beck described from the Lincoln Memorial steps wasn’t a vengeful Old Testament deity enraged by ruling-class corruption, but a benign, grandfatherly one who just wants America to be all it can be.

Some reporters likened 8/28 to a “religious revival,” but it wasn’t nearly that fervid and exciting. For once, the New York Times’s description rang true: It “had the feeling of a large church picnic.”

I confess I liked the Tea Partiers better when they were a little angrier — and when they stuck to the point.

America is a “Christian Nation” only in a trivial sense: that most of us, now and at the founding, are Christians.

And that’s neither here nor there. “Creeping secularism” and insensitively situated mosques aren’t what plagues us — it’s a deluge of red ink falling on the just and the unjust alike.

Renewed faith may save your soul, but it won’t save us from our looming fiscal apocalypse. For that, we need energized citizens who keep their eye on the ball.