"The will to win is the X factor in lot of things -- politics, war and journalism. It can mean a lot, just because in any contest, the psychological dimension is important -- it's the 'yes we can,'" Woodward, who recently finished "Obama's Wars," a two-year book project examining the wars in Iraq and Afghanistan, told the Telegraph in an interview.
When asked if Obama has that "X factor," Woodward said, "It's not clear," the newspaper reported Saturday.
"The troops feel it, the generals feel it. I think he is sincere and genuine, but he keeps a distance, he keeps a distance from people."
Woodward said Obama needs to present a much stronger mission statement for what the United States is doing in Afghanistan.
"It would help the military and it would help the country. I get e-mails from soldiers over there and morale is high, they are focused on their (immediate) missions, but it's not clear to some of them where they fit into the bigger picture.
"We owe those people everything as U.S. citizens, and it's not clear we are giving them everything we could and that includes the definition of the mission," Woodward said.