By Peter Smith / Pittsburgh Post-Gazette

It may be too early to say if Pope Francis' speech to Congress will join the short list of America's most memorable speeches, but he made the most of the moment.

Given the unprecedented setting of a joint meeting of Congress, addressed by a pope who is drawing rapturous crowds wherever he goes in his inaugural U.S. visit, Francis made an articulate and wide-ranging primer of Catholic social teaching.

You can call it a revival of the "seamless garment" touted by the late Chicago Cardinal Joseph Bernadin, who was highly influential among Catholics in the 1980s and 1990s by criss-crossing party lines and weaving opposition to abortion with advocacy for the poor and other disadvantaged. Francis similarly gave both parties things to cheer, quote and cringe over.

Francis drew Americans' attention to two 20th century Catholic converts whose greatest admirers had long been on the Catholic left, Dorothy Day and Thomas Merton, the latter the namesake of the social-justice organization, the Thomas Merton Center of Pittsburgh.

At the same time, Francis also stretched the tent, showing how the values he espoused tie into more universal American values embodied by the man in the Lincoln Memorial and the man who famously spoke in front of it: Martin Luther King Jr.

Francis did not wade into specific legislative controversies before Congress, such as immigration reform or whether to fund Planned Parenthood.

In fact, he delicately alluded to some controversies without saying them by name. He didn't say abortion, but his meaning was clear in saying the "Golden Rule also reminds us of our responsibility to protect and defend human life at every stage of its development."

He didn't say same-sex marriage, but lamented, "Fundamental relationships are being called into question, as is the very basis of marriage and the family." While some casually reduce Francis to being "Mr. Who-Am-I-to-Judge," his use of only one sentence to this year's fundamental change in American marriage law (and with Supreme Court justices present) , may speak to the less-confrontational tone he's taken toward gays and lesbians.

He also never mentioned Islam, even as leading Republican presidential candidates debate the place of Muslims in American political life, and even as the ravages of the self-described Islamic State persist.

"A delicate balance is required to combat violence perpetrated in the name of a religion, an ideology or an economic system, while also safeguarding religious freedom, intellectual freedom and individual freedoms," he said.

But Francis hit other targets square-on, without euphemism. Clearly addressing the American arms industry: "Why are deadly weapons being sold to those who plan to inflict untold suffering on individuals and society? Sadly, the answer, as we all know, is simply for money: money that is drenched in blood, often innocent blood."

Francis' references to Day and Merton were remarkable particularly because their legacies long seemed to run counter to the prevailing conservative agendas among the religious and political right, which include some bishops.

That's changing, as New York Cardinal Timothy Dolan has become a champion for the cause of declaring Dorothy Day a saint. She was the founder of the Catholic Worker movement and was known for courageous and outspoken defense of the poor.

"Her social activism, her passion for justice and for the cause of the oppressed, were inspired by the Gospel, her faith, and the example of the saints," said Francis.

Clearly many of Francis' most impassioned comments before Congress were in defense of the poor. "The fight against poverty and hunger must be fought constantly and on many fronts," he said, paying tribute to reductions in extreme global poverty.

Pope Francis quoted the opening lines of Merton's autobiography, being born in war-torn France and growing into awareness that war between people was echoed in internal spiritual struggles. Merton became a Catholic monk and best-selling writer from the Abbey of Gethsemani in rural Kentucky, from which he engaged some of the most compelling issues of the mid-20th century, including racial divides and war. He "challenged the certitudes of his time and opened new horizons for souls and for the Church," said Pope Francis. Merton pioneered dialogue with such groups as Jews, Muslims and Buddhists, mostly famously the Dalai Lama, who still carries a torch for their brief friendship just before Merton's accidental death in 1968.

"We take those things for granted, but Merton was way out at the forefront of all those things," said Gregory Hillis, a theology professor at Bellarmine University in Louisville, Ky., where the Merton archives are housed.

Pope Francis used the word dialogue about a dozen times in his speech, following up on his invocation to bishops yesterday to "dialogue fearlessly" with everyone.

Mr. Hillis said until today, he didn't even know if Pope Francis knew of Merton, although his words on dialogue are "uncanny" in their similarities to Merton's writings. And the pope's strong emphasis on mercy recalls one of Merton's most quoted lines: "mercy within mercy within mercy."

Merton had corresponded with Pope John XXIII, a reformist often compared to Francis.

The Merton references hit home for the Rev. John Oesterle, a Pittsburgh priest and member of the Thomas Merton Center.

Merton’s "foundation is the contemplative (prayer) approach, so you look at reality more deeply," said Father Oesterle. "His comments on racism and war and peace grew with his experience with God."

But Francis was speaking to a much broader audience than just Catholics, and he also drew on two of the people Americans most look to as moral guides: Abraham Lincoln and Martin Luther King Jr.

Francis cited Lincoln, assassinated 150 years ago this year, as envisioning that "this nation, under God, (might) have a new birth of freedom."

On the 50th anniversary of the epic Selma civil rights march, Pope Francis also cited King’s "dream" of racial equality.

"I am happy that America continues to be, for many, a land of dreams," he said.

As the son of Italian immigrants to Argentina, he made an impassioned plea on behalf of today's migrants, alluding to the ongoing refugee crisis in Europe.

And, a day after canonizing Junipero Serra, an 18th century Spanish missionary to California whose treatment of native peoples remains a historical controversy, Pope Francis said:

"So many of you are also descended from immigrants. Tragically, the rights of those who were here long before us were not always respected. For those peoples and their nations, from the heart of American democracy, I wish to reaffirm my highest esteem and appreciation. Those first contacts were often turbulent and violent, but it is difficult to judge the past by the criteria of the present. Nonetheless, when the stranger in our midst appeals to us, we must not repeat the sins and the errors of the past."

Part of the unprecedented nature of Francis' speech was that for much of American history, distrust of popes as enemies of freedom was viral. One 19th century pope warned of excessive individualism as "Americanism," which didn't help matters. Boston, Philadelphia and Louisville suffered especially fierce anti-Catholic violence.

But recent popes have championed human rights, religious freedom and respect for religious diversity to unprecedented degrees.

Francis even reached out to secular Americans after his Capitol talk, asking for the prayers of believers -- and the good wishes of nonbelievers.

Then he went straight from the corridors of power to meet with the homeless at Catholic Charities.