Five years after the worst terror attack in US history, President George W. Bush said the war against terrorism is "the calling of our generation" and urged Americans to put aside differences and fight to victory. "America did not ask for this war, and every American wishes it were over," Bush said. "The war is not over - and it will not be over until either we or the extremists emerge victorious." Bush, in a televised evening address from his Oval Office in the White House, staunchly defended the war in Iraq, even though he acknowledged that deposed Iraqi President Saddam Hussein was not responsible for the September 11 attacks that killed nearly 3,000 people. He said Saddam's regime, while lacking weapons of mass destruction, was a clear threat that posed "a risk the world could not afford to take." At least 2,600 US servicemen and women have died in Iraq. "Whatever mistakes have been made in Iraq, the worst mistake would be to think that if we pulled out, the terrorists would leave us alone," the president said. "They will not leave us alone. They will follow us." The address came at the end of a day in which Bush honored the memory of the attacks that rocked his presidency and thrust the United States into a costly and unfinished war against terror. It was a day of mourning, remembrance and resolve. Before his address, Bush visited New York, Shanksville, Pennsylvania, and the Defense Department's Pentagon headquarters to place wreaths and console relatives of the victims. "Five years ago, this date - September 11 - was seared into America's memory," the president said. "Nineteen men attacked us with a barbarity unequaled in our history." Bush said that Osama bin Laden, the mastermind of the attack, and other terrorists still are in hiding. "Our message to them is clear: No matter how long it takes, America will find you and we will bring you to justice." Bush said the war on terror was nothing less than "a struggle for civilization" and must be fought to the end. He said defeat would surrender the Middle East to radical dictators armed with nuclear weapons. "We are fighting to maintain the way of life enjoyed by free nations," the president said. Two months before the November elections, he attempted to spell out in graphic terms the stakes he sees in the unpopular war in Iraq and the broader fight against terror. He said Islamic radicals are trying to build an empire "where women are prisoners in their homes, men are beaten for missing prayer meetings and terrorists have a safe haven to plan and launch attacks on America and other civilized nations." "The war against this enemy is more than a military conflict," the president said. "It is the decisive ideological struggle of the 21st century and the calling of our generation." Five years ago, the attacks transformed Bush's presidency and awakened the world to bin Laden and his band of al-Qaida terrorists. While the public has soured on the war in Iraq, which Bush calls the central front in his campaign against terror, the president still gets high marks for his handling of September 11, 2001. Terrorism has been a potent political issue for Republicans, and they hope to capitalize on it in November's elections to determine the future of Congress. GOP lawmakers are anxious about holding control of both chambers, the Senate and the House of Representatives. Congress has approved $432 billion for Iraq and the anti-terror campaign. "The safety of America depends on the outcome of the battle in the streets of Baghdad," the president said. He quoted bin Laden as calling Iraq "the Third World War." "Our nation has endured trials, and we face a difficult road ahead," the president said. "Winning this war will require the determined efforts of a unified country. So we must put aside our differences and work together to meet the test that history has given us." While Bush urged resolve, the two co-chairmen of the commission that studied government actions before and after September 11 and offered recommendations to rectify shortcomings accused the Bush administration and Congress of lacking urgency in protecting the country. Only about half their 41 recommendations, offered in July 2004, have become law. "Where in the world have we been for five years?" said former Democratic Rep. Lee Hamilton, who was joined by his Republican counterpart, former New Jersey Gov. Tom Kean. Hamilton spoke of failures to put first responders on the same radio spectrum so they can talk to each other during an emergency, as firefighters and police officers who died in the World Trade Center could not in 2001. The September 11 attacks changed the political tone in Washington and abroad, but only briefly. "We had an astonishing moment of unity in America and around the world," former President Bill Clinton told a Jewish conference in Washington. That has given way to bitter political divisions between Democrats and Republicans. Many nations that rushed to stand with the United States now accuse the Bush administration of failing to honor human rights, tolerance and diversity of cultures. Still, dozens of lawmakers, Republicans and Democrats alike, joined on the steps of the Capitol on Monday to remember the attacks, singing "God Bless America" as they had done five years earlier. House of Representatives Democratic leader Nancy Pelosi said Monday, "Five years later, we have to continue to move forward with unity, urgency and in the spirit of international cooperation, because we are not yet fully healed and not yet as safe as we should be." Bush began the day in New York with firefighters and police officers at a Lower East Side firehouse. He stood in front of a door salvaged from a fire truck destroyed on September 11. It was a cloudless morning reminiscent of the sunny day when two hijacked planes slammed into the twin towers of the World Trade Center in the heart of New York City. The mourners silently bowed their heads, at 8:46 a.m. and again at 9:03 a.m., marking the moments when the planes slammed into the towers. The attacks killed 2,749 people. Bush spent time talking with the first responders about what they had been through during the last five years, spokesman Tony Snow said. The next stop was in Pennsylvania, where Bush and his wife, Laura, stood without umbrellas in a chilly rain to lay a wreath honoring the 40 passengers and crew killed when United Airlines Flight 93 plowed into a Pennsylvania field. The terrorists apparently had planned to crash the plane into the White House or the Capitol, foiled when passengers stormed the cockpit to take control. Bush had an emotional meeting with relatives of the Shanksville victims. "There were some people who were still clearly grieving about what happened five years ago," Snow said.