Pope Francis arrives in the U.S.

Pope Francis arrived Tuesday from Cuba to start a six-day, three-city tour of America, his first official visit to a nation bitterly divided on global warming, income inequality and other contentious issues that the pontiff is likely to champion.

President Obama and his family, as well as Vice President Joe Biden and his grandchildren, welcomed Francis with handshakes and an honor guard at the military’s Joint Base Andrews, just outside the nation’s capital, as a crowd of well-wishers chanted “Ho, ho! Hey, hey! Welcome to the USA!” Francis clutched his white skullcap, called a zucchetto, in his hand as the wind whipped his white hair and cassock.

The two leaders conversed but did not speak to the crowd before Francis climbed into a modest Fiat sedan and was driven off to spend the night at the Vatican’s diplomatic mission. Still, the brief red carpet ceremony was a heady departure from staid White House protocol, one that reflects the global celebrity and unusual appeal of the first Latin American pope.

Officials are bracing for record-sized crowds, traffic nightmares and bustling vendors when the 78-year-old pontiff rides in his open “popemobile” near the White House, when he celebrates Mass at cavernous Madison Square Garden in New York City, and when he presides over an open air Festival of the Families on the Benjamin Franklin Parkway in Philadelphia, among other stops on a packed itinerary.

For Francis, the visit marks an important effort to revitalize the American Catholic Church, which has been weakened by the sexual abuse scandal and challenged by parishioners who hold more liberal views on contraception, gay marriage and other social issues.

The Argentine-born pope also has a unique opportunity to reach Latinos, the fastest growing group of Catholics in America, who are giving churches their vitality.

U.S. political leaders, in turn, have tried to capitalize on Francis’ immense popularity and moral authority, seizing issues that align most closely with their own agendas.

In his 2 1/2 years as pope, Francis has stressed alleviating poverty and saving the Earth more than traditional teachings against abortion and for traditional families. As a result, when he visits the White House early Tuesday as his first official stop, he will face some Americans whom previous popes almost certainly would have avoided.

Obama has invited several Catholics who support legal abortion, transgender activists and advocates for gay marriage to join a reception on the South Lawn, despite their doctrinal differences with Francis, who recently called the rise of LGBT equality “a new sin against God.”

While some U.S. critics expressed outrage at the invitations, a Vatican spokesman denied reports that the pope’s aides had objected. The Vatican “never comments on those invited by a head of state to be present for a welcoming ceremony of the pope,” said Father Thomas Rosica.

But Vatican officials have hinted that Francis may use his address to both houses of Congress on Thursday -- the first pope to do so -- or another stop in Washington to speak about the sanctity of life and his opposition to capital punishment, issues where he is at odds with Obama.

“This pope is a very independent figure, and we know from his previous travels that we don’t know what he’s going to say until he says it,” said Charlie Kupchan, a top national security advisor to Obama. “And in that respect, we are fully expecting that there will be some messages with which we may respectfully disagree or have differences.”

For all his popularity, Francis will fuel a controversy on Wednesday when he canonizes Father Junipero Serra, an 18th century Franciscan missionary who established the California mission system that helped transform the West.

The ceremony, conducted in Spanish in recognition of Latinos’ growing role in the church, will mark the first such ceremony on U.S. soil, and Serra will be only the 11th Catholic saint with connections to the United States or the colonial era, according to the U.S. Conference of Catholic Bishops.

But making Serra a saint has angered some Native Americans who point to the mission system’s use of floggings and imprisonment for those who tried to leave, and to the spread of deadly diseases that it wrought.

Serra’s supporters say he should be judged as a man of his times, who had flaws but tried to protect native peoples from rape and other crimes by Spanish soldiers.

Obama and Francis met in March 2014 at the Vatican, and the pope subsequently helped broker a diplomatic detente between the United States and Cuba that ended more than five decades of official estrangement when diplomatic ties were restored this summer.

Obama came away from that first meeting speaking of empathy, of the “ability to stand in somebody else’s shoes and to care for someone even if they don’t look like you or share your philosophy.”

The two leaders also agree on the need to slow the burning of fossil fuels to combat climate change, to do more to reduce poverty and income inequality, and on the need for immigration and prison reform to ease suffering.

During the planning for the papal visit, administration officials could scarcely hide their hopes for what it might mean for their joint agenda.

“On many of the big-ticket items,” Kupchan said, “like climate change, like fighting inequality, like fighting poverty, like reaching out to people in distress and people in need, his essential messages will resonate very much with the president’s agenda. And in that respect, we are hoping that his moral authority helps us advance many of the items that we take to be very high on our policy agenda.”

Congressional Republicans, who failed to advance a vote Tuesday to outlaw abortion after 20 weeks, have seized on Francis’ focus on the sanctity of life and his defense of other conservative church doctrine, including opposition to same-sex marriage.

At the same time, Roman Catholics in the GOP presidential field publicly staked out their differences with him.

“I just think the pope was wrong,” New Jersey Gov. Chris Christie said about the U.S. diplomatic thaw with Cuba.

“The pope as an individual,” said Florida Sen. Marco Rubio, “has political opinions. And those, of course, we are free to disagree with.”

For their part, Congressional Democrats released several videos Tuesday urging Francis to use his address to Congress to advance immigration reform, anti-poverty initiatives and climate change.

Advisors to the president recoiled a bit from the political debate swirling around the pope’s arrival and insisted that he was not coming to help Obama’s political agenda.

“This is an opportunity for two men who have so many values in common to talk about the efforts that they are taking in their respective and quite different roles to advance those shared values,” White House Press Secretary Josh Earnest said.

MORE ON POPE’S VISIT TO U.S.:

Pope gets ready to make Junipero Serra a saint, but not in California

A crisis of conscience as pope’s visit falls on Yom Kippur

U.S. Catholic Church at a crossroads: Pope Francis appeals to competing currents