WASHINGTON — Four years ago, President Bush sought to unify a nation divided by a protracted, contested election.

Additional information: Complete text of President Bush's inaugural address

On Thursday, the president took the oath of office for the second time before throngs of supporters, tens of thousands strong, seeking a world unified under the banner of God-given rights to freedom.

"The survival of liberty in our land increasingly depends on the success of liberty in other lands," Bush said. "The best hope for peace in our world is the expansion of freedom in all the world."

Defending freedom across the globe "is the calling of our time."

Braving winter chills and a handful of hecklers, the president said the nation will embrace democratic movements and institutions in every nation, "with the ultimate goal of ending tyranny in our world."

From the time of the Founding Fathers, he said, Americans have proclaimed that "every man and woman on this earth" has rights, dignity and value.

"Across the generations we have proclaimed the imperative of self-government, because no one is fit to be a master and no one deserves to be a slave. Advancing these ideals is the mission that created our nation. It is the honorable achievement of our fathers. Now it is the urgent requirement of our nation's security."

The Bush doctrine, the basis for U.S. involvement in the Middle East, is admittedly risky, said Sen. Bob Bennett, R-Utah, but it is also bold.

"History will remember him primarily for his initiatives for peace in the Middle East," Bennett said. "If he succeeds, he will be one of the greatest presidents ever. If he fails, he will be remembered as someone who gambled big and lost."

The swearing-in ceremony, conducted under a blanket of unprecedented security, featured all the traditional pomp and ceremony. There were military bands playing "Hail to the Chief," stirring hymns, prayers and thousands singing "The Star Spangled Banner" with hands over hearts and tears in their eyes.

The ceremonies even had a bit of a Utah flavor. During the moments leading up to the swearing in, when invited guests were filing in, the Rev. Wintley Phipps sang "Heal Our Land," a song written by U.S. Sen. Orrin Hatch, R-Utah, and Janice Kapp Perry.