The U.S. Conference of Catholic Bishops called for the fortnight in March, outlining several instances of "religious liberty under attack," including the federal contraceptive mandate. They asked dioceses to plan Masses, prayer services, educational events and other activities from June 21 to July 4.

Cardinal Donald W. Wuerl of Washington was the main celebrant of the Mass. Concelebrants included Archbishop Carlo Maria Vigano, the apostolic nuncio to the United States, and Baltimore Archbishop William E. Lori, who is chairman of the U.S. bishops' Ad Hoc Committee for Religious Liberty.

Outside the national shrine before Mass, the crowd joined in the singing of patriotic hymns. The heat was daunting, and the clergy, dressed in heavy white vestments, fanned themselves with missals as they waited to process into the shrine.

Once inside, the pews of the 3,500-capacity of the shrine's upper church quickly filled; other congregants stood, filling the side chapels dotting the church.

The crowd included Knights of Columbus honor guard with their feathered chapeaus to brothers in humble brown robes with dirt-stained sandals.

Rounded out with brass and a full organ, a choir welcomed the procession of bishops, priests and deacons down the aisle to the altar.

Archbishop Chaput began his homily with a quote from Paul Claudel, a French poet and diplomat, who once described the Christian as "a man who knows what he is doing and where he is going in a world (that) no longer (knows) the difference between good and evil, yes and no. He is like a god standing out in a crowd of invalids. ... He alone has liberty in a world of slaves."

The archbishop talked about the idea of freedom of conscience, of knowing right and wrong, equating it with the greater idea of liberty.

Archbishop Chaput said Claudel "spoke from a lifetime that witnessed two world wars and the rise of atheist ideologies that murdered tens of millions of innocent people using the vocabulary of science. He knew exactly where forgetting God can lead."

The modern indifference to morality and the growing sense of moral relativism Blessed John Paul II warned of in the 1993 encyclical encyclical "Veritatis Splendor" ("The Splendor of Truth") can be countered with the values both Americans and Christians hold.

Drawing on the day's Gospel, Archbishop Chaput pointed to Jesus' words: "Render unto Caesar those things that bear Caesar's image, but more importantly, render unto God that which bears God's image" -- in other words, you and me. All of us."

"The purpose of religious liberty is to create the context for true freedom," he said. "Religious liberty is a foundational right. It's necessary for a good society. But it can never be sufficient for human happiness. It's not an end in itself."

He continued, "In the end, we defend religious liberty in order to live the deeper freedom that is discipleship in Jesus Christ. What good is religious freedom, consecrated in the law, if we don't then use that freedom to seek God with our whole mind and soul and strength?"

Archbishop Chaput closed his homily by urging listeners to, "fulfill our duty as citizens of the United States, but much more importantly, as disciples of Jesus Christ."

He received a standing ovation from the congregation, with some in the crowd waving American flags.

At the end of the Mass, Cardinal Wuerl addressed the congregation, tasking his listeners with carrying forth the message of the "fortnight for freedom."

In organizing the "fortnight" foremost among the U.S. bishops' concerns is the U.S. Department of Health and Human Services mandate that employers, including most religious ones, provide insurance coverage for contraception, sterilization and abortion-inducing drugs, which Catholic teaching considers "morally objectionable."

Cardinal Wuerl echoed Pope Benedict's warning of "radical secularism" that threatens to divorce Christians from their freedom of conscience.

"The Holy Father's answer to this radical secularism is, as he explained, 'an engaged, articulate and well-formed Catholic laity,'" the cardinal said.

Before releasing everyone to enjoy the rest their Independence Day celebrations, Cardinal Wuerl concluded: "This call to action should not end with the 'fortnight,' however, and as heralds of the new evangelization, each of us is called to deepen our own appreciation of our faith, renew our confidence in its truth and be prepared to share it with others."