WASHINGTON – President Bush, on the fifth anniversary of the Sept. 11 attacks, said yesterday the war against terror “is a struggle for civilization” in which defeat would leave the Middle East overrun by terrorist states armed with nuclear weapons.

“We are fighting to maintain the way of life enjoyed by free nations,” Bush said in remarks prepared for a prime-time address from the Oval Office. The speech was coming at the end of a day in which he honored the memory of the nearly 3,000 people killed in the attacks that rocked his presidency and thrust the United States into a costly and unfinished war against terror.

“Our nation has endured trials, and we face a difficult road ahead,” the president said.

Before his address, Bush visited New York, Shanksville, Pa., and the Pentagon to pay respect to the victims of the attack and show resolve in the struggle against Islamic militants.

“America did not ask for this war, and every American wishes it were over,” the president said. “And so do I. But the war is not over – and it will not be over until either we or the extremists emerge victorious.”

“If we do not defeat these enemies now, we will leave our children to face a Middle East overrun by terrorist states and radical dictators armed with nuclear weapons,” Bush said. “We are in a war that will set the course for this new century and determine the destiny of millions across the world.”

White House officials said Bush’s speech was not intended to outline new strategy. Rather, it was portrayed as an appeal for unity and a commitment to win the struggle against terror at a time when the war in Iraq is highly unpopular. There was no mention of Iraq in the excerpts of the speech, but officials said Bush would talk about it in his address.

“This struggle has been called a clash of civilizations,” the president said. “In truth it is a struggle for civilization.” He said the United States was standing with democratic leaders and reformers, offering a path away from radicalism.

“Winning this war will require the determined efforts of a unified country,” the president said. “So we must put aside our differences and work together to meet the test that history has given us. … We will defeat our enemies.”