"We need your message to reject this dictatorship of relativism and embrace a culture of justice and truth," Bush said in brief remarks welcoming Benedict to the White House. "In a world where some see freedom as simply the right to do as they wish, we need your message that true liberty requires us to live our freedom not just for ourselves, but in a spirit of mutual support."
The pontiff's 90-minute stay at the White House was accompanied by the kind of pomp and pageantry rarely seen even on grounds accustomed to routinely welcoming royalty and the world's most important leaders.
Lampposts fluttered with flags in the red-white-and-blue of America and yellow-and-white of the Holy See. The vast South Lawn was filled to nearly bursting with the largest crowd of Bush's presidency, requiring a large television screen so those further back could see. Groups of Boy and Girl Scouts in their uniforms and members of the Knights of Columbus wore their traditional brightly colored feather headgear. Thousands unable to get inside filled Washington's streets as well, playing music and waving banners as they waited for a hoped-for glimpse of the pontiff passing by later in his popemobile.
An almost serenely quiet papal arrival at the White House preceded the program as Benedict's limousine pulled up the driveway to a greeting from Bush and his wife, Laura. The two leaders strolled along a red carpet to a platform set up on the lawn, and sat side-by-side as the Marine Band played the national anthem of the Holy See while a 21-gun salute from the Ellipse sprayed gray smoke into the air. Famed American soprano Kathleen Battle sang "The Lord's Prayer." The U.S. Army Old Guard Fife and Drum Corps, dressed in colonial garb, marched past the two leaders.
Four toddlers sat on the grass with handmade signs. One read "We love you pope of hope" and other showed a birthday cake -- chocolate -- with an 81 on it. The crowd spontaneously sang "Happy Birthday" early in the ceremony, and a formal, more full-throated version came at the end.
"God bless America," said Benedict robustly, to cheers from the excited throng.
The pontiff has said he was looking forward to meeting a "great people and a great church" during his first papal journey to the United States. The six-day trip to Washington and New York City coincides not just with his birthday, but the three-year anniversary of his ascendancy to the Roman Catholic Church's top position. Nurturing the U.S. flock is a sensitive and important mission for Benedict at a time, not just of ongoing scandal in the American church but amid his campaign to tamp down secularism and re-ignite faith worldwide.
"I trust that my presence will be a source of renewal and hope for the church in the United States and strengthens the resolve of Catholics to contribute even more responsibly to the life of this nation of which they are proud to be citizens," Benedict said at Bush's side.
Bush showed off America to its important visitor, ticking off what he said are its best virtues: a nation of prayer and compassion, a nation that believes in religious liberty and welcomes the role of faith in the public square, and one that is the most "innovative, creative and dynamic country on Earth" but also among the most religious.
"Most of all, Holy Father, you will find in America people whose hearts are open to your message of hope," Bush said.
But while acting the proud father, Bush also seemed to suggest that America could use a little tough talking-to by the pontiff.
"In a world where some treat life as something to be debased and discarded, we need your message that all human life is sacred and that each of us is willed, each of us is loved, and each of us is necessary," the president said, drawing sustained applause from the lawn.
Adela Arguello, a Department of Homeland Security worker from Miami flew in for the events. "We're living in very terrible times and any message like this is important," she said. "He needed to come."
"How often in life do you get to sing Happy Birthday?" said Brenda Hawk, a Sunday school teacher from Centreville, Va. "Even if you're not Catholic, it's darn cool!"
The president kicked off the unprecedented series of papal festivities on Tuesday, by motoring to Andrews Air Force Base just outside Washington to meet Benedict's plane, something he's never done for any leader. While the pontiff received a screaming, cheering reception befitting a rock star from hundreds of Catholic students and others on the tarmac, Bush stood back in the unusual role of second fiddle.
From the South Lawn, Bush and his wife, Laura, escorted the pontiff into the White House's Blue Room to introduce him to relatives and serve birthday cake. The leaders then were to hold talks in the Oval Office, the 25th meeting between a Roman Catholic pope and a U.S. president -- sessions that span 89 years, five pontiffs and 11 American leaders.
In the evening, the Bushes are hosting a swank East Room dinner in Benedict's honor, complete with Bavarian-style food to celebrate his native Germany. But a meeting between Benedict and U.S. bishops at the Basilica of the National Shrine of the Immaculate Conception in Washington was preventing him from dining with the president.
These two leaders share much common ground, particularly in opposing abortion, gay marriage and embryonic stem cell research. But there are plenty of differences.
They disagree over the war in Iraq, the death penalty and the U.S. trade embargo against Cuba. Benedict also speaks for environmental protection and social welfare in ways that often run counter to Bush policies. And the pontiff told reporters on his plane that he planned to bring up immigration policy with Bush during their private Oval Office meeting. Benedict has talked forcefully in the past about the damage caused by punitive immigration laws.
White House press secretary Dana Perino predicted that Iraq would not "dominate the conversation in any way." If it comes up, it's likely to be focused almost exclusively on the fears of the Christian minority in Muslim-majority Iraq, she said.
Another topic that will get cursory attention, if any, is the clergy sex abuse scandal that continues to devastate the American church. Perino called it not "necessarily on the president's top priorities" for the meeting.
On his flight to the United States, Benedict said he was "deeply ashamed" by the scandal and "will do everything possible to heal this wound." No pope has been to the United States since the case of a Boston serial molester triggered a crisis that spread throughout the U.S. and beyond in 2002.
The Associated Press contributed to this report.