– On his first papal trip outside Rome in 2013, Pope Francis rode a small boat in the Mediterranean to lay a wreath where scores of migrants had drowned seeking refuge in Europe. “We have fallen into globalized indifference,” he said above the watery graveyard.

For the man born Jorge Mario Bergoglio, whose grandparents and father emigrated from Italy to Argentina in 1927, defending the human rights of migrants and refugees is at the core of his papacy.

When he speaks next month at Independence Mall, the plight of desperate people on the move is expected to be a chief theme.

Details of his talk are under wraps, but simply the plan for a speech on the topic has energized Catholic immigrants and others across country — hopeful that the pontiff will use the bully pulpit to even more forcefully advocate on a front-line issue in the United States and the wider world.

“Francis sees the rise of nativist and anti-immigrant feeling as signs of a dangerous moment in politics, and his mission is to offer an alternative vision,” said Austen Ivereigh, author of “The Great Reformer: Francis and the Making of a Radical Pope.”

His passion for immigrants includes a critique of rampant consumerism and concentrated wealth, which drive huge population movements. The pope’s comments, Ivereigh said, speak to “the temptation for wealthy countries to raise the drawbridge.”

He and other experts noted that Francis’ predecessors in recent decades have spoken up for migrants. But for this pope, immigration is personal. He knows the pain and the hope of leaving one country for another, and the vulnerability of the migrant life.

“When he speaks about their human dignity,” John Allen, associate editor of the Catholic-interest website Crux, wrote recently, “it’s not just a matter of social justice, (but) an homage to his ancestors.”