Republican lawmakers such as Ohio's Candice Keller have openly speculated that the divide over abortion rights might lead to civil war. Last month, Keller drew explicit comparisons with the antebellum situation over slavery, telling the Guardian: "Whether this ever leads to a tragedy, like it did before with our civil war, I can't say."

Earlier this month, the Guardian revealed that the Washington state republican legislator Matt Shea had also speculated about civil war, and the "Balkanization" of America, predicting that Christians would retreat to "zones of freedom" such as the inland Pacific north-west, where Shea is campaigning for a new state to break away from Washington.

Asked on a podcast if the two halves of the country could remain together, Shea said: "I don't think we can, again, because you have half that want to follow the Lord and righteousness and half that don't, and I don't know how that can stand."

Shea has introduced a bill -- unlikely to pass -- which would criminalize abortion in the state.

Along with legislators, the notion of a civil war over abortion has been finding traction in the media organs of the Christian right.

In the past year, Charisma magazine, the leading media voice of Pentecostal and charismatic Christians, has run at least half a dozen articles contemplating the possibility of an imminent civil war in America. One recent article profiles pastor, broadcaster and author Michael L Brown, who blames a "coming civil war" on "militant abortionists".

Brown told Charisma: "A civil war is coming to America, only this time, it will be abortion, rather than slavery, that divides the nation".

An upcoming book from Brown also warns that abortion is among the signs that "the demonic spirit of Jezebel is powerful in America". In another column this month Brown wrote: "A civil war is certain. The only thing to be determined is how bloody it will be."

This year the Christian televangelist Rick Joyner has, on his ministry's website and other Christian right outlets, been offering detailed descriptions of a civil war he believes to be coming on the basis of his own prophetic dream.

Abortion is one of the key reasons he thinks that war is imminent.

Joyner also turned to Charisma magazine at one point to describe a dream, which he says he had late last year. "We are already in the first stages of the Second American Revolutionary/Civil War," he wrote. "In the dream, I saw that we had already crossed that line and it is now upon us, so we must change our strategy from trying to avoid it to winning it."

Andre Gagne is an associate professor of theology at Concordia University in Montreal, who researches the religious right. He says that while Charisma magazine may be unfamiliar to secular and liberal Americans, it is "absolutely representative" of charismatic and Pentecostal Christians on abortion, and as such speaks for "millions of people".

He says that the idea that abortion may lead to civil war has percolated for some time on the Christian right. Gagne says that the Christian right's fight against abortion is driven by real belief, and real fear.

"The Christian right believes that if they don't engage politically, and try to influence social issues, God will judge America, and he will judge them," Gagne said.

But is the possibility of an abortion-centred civil war likely?

Journalist Robert Evans hosts the breakout podcast It Could Happen Here, which canvases scenarios for a new American civil war.

He said that the Christian right "generate a lot of the extremist language in mainstream politics", but that "there's more talk about violent insurrection from the white nationalist right than the Christian right, because there's less faith in politics".

For now, as demonstrated by the abortion bills passed in several states in an apparent attempt to get a case to the supreme court and overturn abortion rights nationally, the Christian right is reaping dividends from engaging with the political process.

But, Evans notes, the danger may come if "they see victory slip from their grasp".

And unlike the fractious and small subcultures of the racist far right, "the Christian right is really good at keeping people working together for years at a time".