Before September 11, President George W Bush kept his evangelical Christian beliefs largely to himself.
By Tom Carver
BBC Washington correspondent
He had turned to God at the age of 40 as a way of kicking alcoholism, and his faith had kept him on the straight and narrow ever since, giving him the drive to reach the White House.
Bush convinced God wants him to engage the forces of evil
But all that changed on the day of the attacks on the Pentagon and World Trade Center.
Those close to Mr Bush say that day he discovered his life's mission.
He became convinced that God was calling him to engage the forces of evil in battle, and this one time baseball-team owner from Texas did not shrink from the task.
"We are in a conflict between good and evil. And America will call evil by its name," Mr Bush told West Point graduates in a speech last year.
In this battle, he placed his country firmly on the side of the angels.
"There is wonder-working power in the goodness and idealism of the American people," he said in this year's State of the Union address.
This concept of placing America in God's camp sticks in the throat of a lot of American clergy.
"It is by no means certain that we are as pure as the driven snow or that our international policy is so pure," says Fritz Ritsch, Presbyterian minister in Bethesda, Maryland.
The Reverend Ritsch says it also makes their job as clerics harder by giving Christians in America an easy way out.
They do not need to examine their souls because their president has told them they are on the side of good.
"There is an opportunity here for spiritual enrichment in this country that is just getting missed."
Battle with anti-Christ
In fact, nearly all the mainline churches in America oppose this war, including Mr Bush's own church, the United Methodists.
Mr Bush is certainly not the first president to invoke God in time of war, but his approach is markedly different from his predecessors.
Does Bush believe he fights a titanic battle with the anti-Christ?
During America's Civil War, Abraham Lincoln did not claim that God was on his side.
In fact, in his famous second inaugural address, he said the war was a curse on both armies: "He gives to both North and South this terrible war as the woe due to those by whom the offence came."
Yet Mr Bush's rhetoric does have a huge audience.
One in three American Christians call themselves evangelicals and many evangelicals believe the second coming of Christ will occur in the Middle East after a titanic battle with the anti-Christ.
Does the president believe he is playing a part in the final events of Armageddon?
If true, it is an alarming thought.
But he would not be alone, as 59% of all Americans believe that what is written in the Bible's Book of Revelation will come to pass.
Tim LaHaye is an evangelical minister who has written 10 best-selling novels based on the Book of Revelations.
With exquisite timing, his 11th, called Armageddon, will be published next week.
By combining the apocalypse with a Tom Clancy style, Mr LaHaye has found a winning formula.
After the attacks on the World Trade Center, the minister became America's best-selling novelist in 2001, beating even John Grisham.
In his latest novel we see the anti-Christ, armed with nuclear weapons, setting up camp at New Babylon in Iraq.
The millions of Americans who believe in the biblical prophecies see this war in a very particular way and among them, George Bush's stark talk of good versus evil plays very well.
If America prevails, millions will say it was divinely ordained.
But many others will suspect that it had more to do with the power of American weaponry than the active intervention of the Almighty.