Philadelphia, United States - For a man who leads the world’s 1.2 billion Catholics, his first trip to the US will be remembered as highly political.

While he brought delight and joy to the hundreds of thousands - perhaps millions - who turned out to see him, there were some who felt Pope Francis strayed too far from matters of faith.

During his three-city trip, he talked of things anout which he is clearly concerned.

Immigration was top of the list. Here was a pope, himself the son of Italian immigrants to Argentina, using symbols of the US to emphasise his point.

Standing behind the lectern used by Abraham Lincoln to deliver the Gettysburg Address, next to a statue of George Washington, and in front of the hall where the American constitution was debated and adopted, he reminded everyone this was a country built on immigration.

He told the crowd of thousands, many of them Latino immigrants themselves, "I ask you not to forget that, like those who came her before you, you bring many gifts to your new nation. You should never be ashamed of your traditions."

His comments came just days after he raised the same issue in a rare address to a joint session of Congress. He called for compassion towards immigrants as the presidential campaign has brought a harsher tone on the issue in recent months.

'Acting like a leftist'

The pope has also raised climate change and income equality. It’s not the first time he’s raised the issue of the planet. When he talked about it in the past, Rick Santorum, a devout Catholic who would like the Republican nomination for president, said such issues should be left to the scientists. The pope holds a Master’s degree in Chemistry.

Pope Francis highlights immigration in Philadelphia
One Catholic congressman staged his own boycott of the leader of his church, refusing to attend the joint address, claiming the pope was acting like a leftist politician and, therefore, should "expect to be treated like one".

But that assumes the pontiff fits neatly into the American categorisation of politics, that taking one stance on one issue must mean he follows one party.

Francis also talked about the importance of family. And what was a clear reference to a recent decision by the US Supreme Court to endorse same-sex marriage nationwide he said, "I cannot hide my concern for the family, which is threatened perhaps as never before, from within and without. Fundamental relationships are being called into question, as is the very basis of marriage and family."

He also addressed the issue of abortion, saying human life had to be protected and defended "at every stage of its development".

Both points drew loud cheers from Republicans.

There is nothing unusual with popes taking a stance on political issues.

John Paul II became personally very close to President Jimmy Carter but found a committed anti-communist in Ronald Reagan and the pope supported many of his words and actions during the Cold War with Soviet Russia.

But late in his papacy, John Paul also strongly condemned the US invasion of Iraq, while George W Bush sat next to him during a ceremony in the Vatican.

Francis comes from a long line of popes, popular in the US and not afraid to use that popularity to raise political issues he believes are central to his faith and to his beliefs.

He wields significant influence. That alone makes his position highly political.

Source: Al Jazeera