WASHINGTON —  The United States president must handle the weight of the world even in the best of times. But in times of crisis, the Oval Office can seem like a lonely place, a responsibility bigger than any one person can manage.

No truth seemed more self-evident than that after the attack on Sept. 11, the worst in U.S. history. It is one of the greatest challenges ever to confront a president.  

After the attack, President Bush said he will face that challenge without relent.  But even before then, he made it clear that he is not doing the job on his own.

"I start with being on bended knee every morning. Seriously," the president said in the beginning days of his administration.

American presidents have often turned to God, and President Bush has never been shy about his faith. 

"That's where he gets his comfort. That's where he gets his balance. That's where he gets his perspective," said Bush friend and Commerce Secretary Don Evans.

Bush is among the more devout occupants of the presidency, though the weight of the office has driven even doubters to their knees.

"Even Abraham Lincoln, who was a religious skeptic and was criticized for being a religious skeptic, came to draw great strength from his faith as the civil war crisis deepened," said Allan Lichtman, professor of history at American University.

But Bush has no such doubts.  He told Fox News he prays in the Oval Office and reads the Bible every day.

Perhaps that's why he sees the war on terror in biblical terms of good versus evil. Bush often refers to Usama bin Laden, the suspected terrorist blamed for the attacks, as the "evil one" and his Al Qaeda network as "evildoers."

And Evans said the president sees fighting terrorism as the purpose of his presidency and perhaps even a calling from God.

"He understands what his calling in life is. He understands that he's been called at this moment," Evans said. 

The president is known for being decisive, even on controversial matters, and doesn't  second-guess himself. The reason, one aide said, is that he thinks someone else is helping to guide him.