Updated

President Bush said Wednesday that rebuilding Iraq and Afghanistan while battles rage is proving difficult, and "we're learning as we go."

The president looked back to the experience of World War II, the deadliest conflict in history, in again asking the country for patience as the United States fights two wars.

"We've assumed this obligation before," Bush told more than 1,000 graduates of the U.S. Air Force Academy at a cold, drizzly football-stadium ceremony.

"After World War II we helped Germany and Japan build free societies and strong economies," Bush said. "These efforts took time and patience, and as a result Germany and Japan grew in freedom and prosperity. Germany and Japan, once mortal enemies, are now allies of the United States. People across the world have reaped the benefits."

Yet the president acknowledged one of the many differences between the global conflict six decades ago and the ones that began under his watch: today's wars are not over.

"In Germany and Japan, the work of rebuilding took place in relative quiet," Bush said. "Today we're helping emerging democracies rebuild under fire from terrorist networks and state sponsors of terror. This a difficult and unprecedented task, and we're learning as we go."

Bush says the country must not lose its nerve. He said terrorist enemies, using the media and the never-ending news cycle, attack innocent people to weaken American resolve.

"We need to prevail not just in the battle of arms, but also in the battle of wills," Bush said. "And we need to recognize that the only way that America can lose the war on terror is if we defeat ourselves."

Bush's message was overshadowed by a blistering tell-all book by his former press secretary, Scott McClellan. The former voice of the White House, McClellan writes that Bush favored propaganda over honesty and candor in selling the war to the American public.

McClellan strikingly calls the Iraq war a "serious strategic blunder." His scathing account of Bush's leadership drew dominant news coverage and lit up many Internet blogs.

White House press secretary Dana Perino said that McClellan's account was puzzling and sad, and that Bush had more important matters than commenting on books by former staffers.