President Bush, looking back on eight tumultuous years, said Thursday that his decisions in office have kept the country safe from another terrorist attack as he urged the incoming administration to never let down its guard. 

Delivering his farewell address from the White House, Bush called the approaching inauguration of President-elect Barack Obama a "moment of hope and pride" for the country. He said he is "filled with gratitude" for the opportunity to serve. 

But he also cautioned Obama to be vigilant, warning that the gravest threat to the country continues to be another terrorist attack. 

"We have faced danger and trial, and there's more ahead. But with the courage of our people and confidence in our ideals, this great nation will never tire, never falter and never fail," Bush said, reprising a line he delivered shortly after the Sept. 11 attacks. 

The outgoing president hailed the progress made in Afghanistan and Iraq during his two terms. He described his administration's military campaigns as a fight against murderous fanatics that the United States and its allies are winning. And he said he's always acted in the country's best interest, though there have been "setbacks" along the way.  

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"I vowed to do everything in my power to keep us safe. ... And with strong allies at our side, we have taken the fight to the terrorists and those who support them," he said. "There is legitimate debate about many of these decisions. But there can be little debate about the results. America has gone more than seven years without another terrorist attack on our soil." 

Bush acknowledged "things I would do differently if given the chance." But he said: "I have followed my conscience and done what I thought was right. You may not agree with some tough decisions I have made. But I hope you can agree that I was willing to make the tough decisions."

Bush said the country never wavered in promoting "human liberty, human rights, and human dignity." He delivered his address in front of an audience in the East Room of the White House. 

Bush has made several appearances over the course of the week, defending his overall record as "solid" and declining to engage in what he called "self-pity." He has said the desire to protect the country always trumped a desire to be popular and appease his critics. 

Bush, whose presidency has been assailed by criticism over his handling of the Iraq and Afghanistan wars, said Thursday that Afghanistan has gone from a nation controlled by the oppressive Taliban to one promoting democracy and fighting terrorism. He said Iraq has gone "from a brutal dictatorship" to an "Arab democracy." He said Iraq has gone from an enemy to a friend of the United States. 

He said the "only practical way" to protect Americans is to advance the causes of liberty and freedom so other nations do not fall into the hands of those who support terror. 

"I have often spoken to you about good and evil. This has made some uncomfortable. But good and evil are present in this world, and between the two there can be no compromise," Bush said. "This nation must continue to speak out for justice and truth."

The final months of Bush's presidency were marked by what's been called the worst economic crisis since the Great Depression. But Bush defended his decision to send billions of government dollars into the financial markets to safeguard the economy against collapse. 

And he said the nation must continue to "engage the world."

"Our enemies are patient and determined to strike again. America did nothing to seek or deserve this conflict. But we have been given solemn responsibilities, and we must meet them. We must resist complacency. We must keep our resolve. And we must never let down our guard," he said.