A fast-moving Pope Francis plunged into his first U.S. visit with gusto Wednesday, embracing the adulation of jubilant crowds as he crisscrossed Washington and confronted enduring controversies that included global warming, immigration and the clergy abuse scandal.

The popular pontiff, who has captured the imagination of religious and secular Americans with his humble style, began to establish an in-the-flesh identity as a committed champion of the poor, the dispossessed and the planet. But he also positioned himself as a loyal adherent of church teachings and hierarchies that are much less popular than he is, pushing back, Vatican watchers said, on efforts to enlist him on either side of the culture wars.

The pope thrilled a White House gathering by introducing himself as the son of immigrants and aligning himself with President Obama’s climate-change efforts. But he also echoed the call for religious liberty that conservatives claim as resistance to same-sex marriage and other fast-changing social mores.

At a prayer meeting later, he urged U.S. bishops to avoid the harsh and divisive language of modern politics. But he also praised their “courage” in handling the sexual-abuse crisis, provoking swift outrage from victims’ advocates.

The pope started his second day in the United States with a visit to the White House, where he spoke on the South Lawn. (Associated Press)

Later in the day, he made an unscheduled stop to meet with the Little Sisters of the Poor, the order that has sued the Obama administration over the Affordable Care Act mandate that employers provide contraception coverage.

The nuances of his message may have been lost, if it was heard at all, on the giddy throngs who rose early and waited hours to catch the briefest glimpse of the pontiff. Local workers largely heeded pleas to work from home, leaving city streets strangely empty for the tens of thousands of faithful, many of whom traveled from around the hemisphere to see the first Latin American pontiff.

With the weather at its Washington-in-autumn best, every move of the motorcade was greeted by cheering crowds, starting with a group of Catholic schoolchildren who gathered outside the Apostolic Nunciature, or Vatican embassy, to cheer his departure for the White House.

“We love Francis, yes we do! We love Francis, how ’bout you?” they hollered.

The first day of the pope’s five-day U.S. tour was a busy and active one. The pontiff’s morning address to administration officials on the White House lawn was followed by a private meeting with the president. The parade that followed ended at the Cathedral of St. Matthew the Apostle, where the pope held a prayer meeting with hundreds of bishops from around the country.

After a brief rest, the papal entourage moved to the Basilica of the National Shrine of the Immaculate Conception adjacent to Catholic University, where the pope celebrated his first American Mass in front of some 20,000 ticketed celebrants, and he canonized a saint for the first time on U.S. soil. His long day ended where it had started about 12 hours earlier, with Francis greeting a crowd of Catholic students in front of the Vatican embassy, where he would again spend the night.

In a midday prayer service at the Cathedral of St. Matthew the Apostle in Washington, Pope Francis said that sex crimes must “never repeat themselves.” (AP)

Along the pope’s parade route near Lafayette Square, Secret Service agents had to slow people down when the crowds threatened to become dangerous.

“It was like a Black Friday at a department store,” Christopher Hale, executive director of Catholics in Alliance for the Common Good, said of the rush, as priests nearby heard the confessions of the waiting faithful.

Inside the White House fence, the pope was quick to address climate change.

“Mr. President, I find it encouraging that you are proposing an initiative for reducing air pollution,” the pontiff said. “Accepting the urgency, it seems clear to me also that climate change is a problem which can no longer be left to a future generation.”

“When it comes to the care of our ‘common home,’ we are living at a critical moment of history,” he said. “We still have time to make the changes needed.”

Francis’s remarks also focused on the need to provide comfort to those at the margins of society.

The event was attended by thousands of dignitaries, among them Vice President Biden; his wife, Jill; Ethel Kennedy; Secretary of State John F. Kerry; and Cardinal Donald W. Wuerl, the archbishop of Washington.

In his warm welcome of the pope, Obama called Francis a living example of Jesus and a figure of humility and simplicity.

“I believe the excitement around your visit, Holy Father, must be attributed not only to your role as pope but to your unique qualities as a person,” the president said in welcoming the pontiff.

“In your humility, your embrace of simplicity, in the gentleness of your words and the generosity of your spirit, we see a living example of Jesus’s teachings,” Obama said.

“You call on all of us, Catholic and non-Catholic alike, to . . . ensure that every human being is able to live in dignity, because we are all made in the image of God,” he said.

Pope Francis addressed the president in accented but clear English, introducing himself to the crowd in his first sentence as “the son of an immigrant family” — his parents came from Italy to Argentina — and describing the United States as “largely built by such families.”

Following the remarks on the White House lawn, Francis, clothed in flowing white robes, basked in the adulation, smiling and waving to delirious bystanders as he passed in the bubble-topped popemobile. Security guards plucked children from the crowd, and the pope kissed and blessed them before passing them back.

The circuit along 15th Street, Constitution Avenue and 17th Street in Northwest, and past the Washington Monument, was a love fest, with the pope leaning out the side openings of his car and waving to the cheering bystanders as if to friends.

Many of the signs were in Spanish — “Yo [Heart] Papa Francisco!” was popular — reflecting the enthusiasm among Latinos for the Argentine pontiff.

Francis spoke repeatedly of the role of immigrants in shaping the United States. At his first U.S. Mass, which he celebrated in Spanish at the basilica, he canonized Junípero Serra, an 18th-century Spanish missionary in California.

On Thursday, Francis will make the first address by a pope to a joint meeting of Congress. Afterward, he is scheduled to appear on the balcony of the West Front of the Capitol to greet a crowd that was expected to swell to about 50,000.

After the parade Wednesday, the pope prayed with several hundred American bishops at St. Matthew. In the soaring church that hosted the funeral of President John F. Kennedy, the pope noted the bishops’ continental responsibilities.

“From your great coastal cities to the plains of the Midwest, from the Deep South to the far reaches of the West, wherever your people gather in the Eucharistic assembly, may the pope be not simply a name . . . but a felt presence, sustaining the fervent plea of the bride: ‘Come, Lord!’ ”

Francis then brought up immigration, a political issue in the United States.

“I am well aware of the immense efforts you have made to welcome and integrate those immigrants who continue to look to America, like so many others before them, in the hope of enjoying its blessings of freedom and prosperity,” he said.

The pope also mentioned the Devil, “the evil one, [who] roars like a lion, anxious to devour” joy. And he listed the church’s challenges in the future:

“The innocent victim of abortion, children who die of hunger or from bombings, immigrants who drown in the search for a better tomorrow . . . the victims of terrorism, wars, violence and drug trafficking, the environment devastated by man’s predatory relationship with nature.”

But it was his comment on the sexual-abuse scandal that drew a swift reaction:

“I realize how much the pain of recent years has weighed upon you, and I have supported your generous commitment to bring healing to victims — in the knowledge that in healing we, too, are healed — and to work to ensure that such crimes will never be repeated.”

Marci Hamilton, a law professor at the Cardozo School of Law who has represented hundreds of sexual-abuse victims, said she wished the pope had focused more on the victims, rather than the church.

“I think the survivors had hoped for more attention on their suffering,” Hamilton said. “It’s also shocking to hear him praise the bishops in their handling of child sex abuse when there are so many states that cut out the victims from the justice system.”