WASHINGTON, Feb 3 (AFP) - US President George W. Bush, mocked by some during the campaign for saying his favorite philosopher was Jesus, has brought religion back to center stage in US politics with a rarely-seen zeal.

Moments after taking his hand off the Bible at his inauguration, Bush -- a Methodist who reads scripture daily -- hinted at a divine national purpose by suggesting that "an angel rides in the Whirlwind and directs this Storm."

In his self-created whirlwind, Bush declared the day after he took office a national day of prayer; quickly unveiled a plan to help children in ailing public schools seek private -- perhaps parochial -- institutions; and floated another to arm faith-based entities on the front lines of the fight against homelessness and hunger with federal funds.

"For the first two weeks in office, it is unprecedented in modern history for a president to make religion and religious involvement in public policy such a leitmotif," said Allan Lichtman, a presidential historian at American University here.

"Others have emphasized religious roots, used religions imagery, met with religious leaders, infused their speeches with religious language," like Ronald Reagan's 'shining city on a hill' imagery, drawn from Augustine, he added.

But rarely, Lichtman said, has religion played such an important role so early in an administration, despite exceptions like John F Kennedy, the first Catholic president, who faced critics wrongly worried he would answer to the Vatican.

Bush has credited the Reverend Billy Graham, a spiritual adviser to several past US presidents, with helping him quit drinking, which he decided to do the morning after his 40th birthday in July 1986.

Faith "has sustained me in moments of success and in moments of disappointment. Without it, I'd be a different person. And without it, I doubt I'd be here today," the president said Thursday at the annual National Prayer Breakfast.

The emphasis Bush has placed on religion since taking office has rattled critics who warn what Bush proudly touts as his "compassionate conservative" programs amount to a breach in the constitutional wall between church and state.

"The president ought to stick to running the country, and leave the soul of the nation to its religious leaders," said Rob Boston, spokesman for the watchdog Americans United for Separation of Church and State.

At issue is the First Amendment of the US Constitution, which reads in part: "Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof."

The clamor from opponents grew loud enough that Bush used the prayer breakfast to reassure Americans he did not mean to impose his religious views on the nation.

"America's Constitution forbids a religious test for office. And that's the way it should be. An American President serves people of every faith, and serves some with no faith at all," the president insisted.

Yet he won his loudest applause when he pledged: "The days of discriminating against religious institutions simply because they are religious must come to an end."

That approach may enjoy widespread approval in the United States, where a poll last year by the nonpartisan Pew Research Center found 70 percent of the people say their president ought to have strong religious beliefs.

The survey, which had a margin of error of plus or minus 2.5 percentage points, also found 45 percent go to religious services at least once a week.

Despite the constitutional provision, subtle reminders of religion abound in the dealings of government: US currency bears both the latin "E pluribus unum" -- out of many, one -- and "In God We Trust."

Most witnesses in courtrooms swear to tell the truth with one hand on a Bible, "so help (me) God," -- and the one Bush used for his swearing-in was reportedly the one used at George Washington's inaugural, the very first such ceremony in US history.