In 1787, at the age of eighty-one, Benjamin Franklin addressed the Constitutional Convention: “I have lived, Sir, a long time, and the longer I live, the more convincing proofs I see of this truth: that God governs in the affairs of men. And if a sparrow cannot fall to the ground without his notice, is it probable that an empire can rise without his aid? We have been assured, Sir, in the sacred writings, that ‘except the Lord build the House, they labor in vain that build it.’ I firmly believe this; and I also believe that without his concurring aid, we shall succeed in this political building no better than the builders of Babel: We shall be divided by our little, partial, local interests, our projects will be confounded, and we ourselves shall become a reproach and byword down to future ages.”

What he said is still true. As a nation, the United States is built on a religious anthropology. It presumes a moral architecture shaped deeply by biblical thought and belief.

Yes, Franklin was a Deist, and he’s better known for his romantic escapades than for his religious piety. It’s also true that classical and Enlightenment ideas played an important role in the founding. But the Enlightenment itself is inconceivable outside the Christian culture from which it emerged, and from which it borrowed its moral vocabulary.

What we believe—or don’t believe—about God profoundly shapes what we believe about the nature of the human person and the purpose of human society. It follows that the more we remove God from our public life, the more we remove the moral vocabulary that gives our public institutions meaning. The more secularized we become, the more we undermine the common good and the more we feed the problems that are hurting us as a nation.

These are strong claims. But they were obvious to the founders, many of whom were Christian, and all of whom understood and respected the role of religious faith in sustaining a healthy republic. Politics is the arena wherein the struggle between truth and lies, justice and injustice, takes place. No nation’s political life can be honest—and no government can serve the needs of its people—unless it welcomes the deepest convictions of its citizens into public debate.

In the American tradition, people have a duty to bring their beliefs to bear on every social, economic, and political problem. That’s not just a privilege, and it’s not just a right. It’s a duty. For American Christians, to do so is a demand of the Gospel and a practical expression of Christian love. Obviously, we have an obligation to respect the dignity of other people and their own basic rights as well. We’re always bound to treat other people with charity, justice, and prudence. But that can never be an excuse for our own inaction or silence.

Unless we live our faith not just in our private behaviors but also in our public actions, including political involvement, we’re living a lie. We’re lying to ourselves, because we’re not really serious about our faith unless we have the zeal and the courage to witness to it. And we’re also cheating our fellow citizens. In a democracy, the best gift any of us can give to our country is the public witness of our convictions. Democracy depends on an honest, unashamed, public struggle of ideas. If we withhold our religious and moral beliefs from our political debates because of a misguided sense of good manners, we are not being “polite.” On the contrary: We’re stealing from the public conversation.

In Catholic moral tradition, patriotism is associated with the Fourth Commandment: You shall honor your father and mother, a duty that the Baltimore Catechism describes as “filial piety and patriotism.” In other words, patriotism is a virtue, a genuinely noble thing, when it roots itself in a love for the best qualities in our homeland and our fellow citizens. This is why military service and public office are not just socially useful jobs but—at their best—good and honorable vocations.

Politics can be a rough and messy business, and free societies rarely look dignified. But that doesn’t subtract from the importance of the law, which is tied intimately to the search for human justice and happiness. The messiness of politics doesn’t diminish the urgency of our public witness, or the importance of the sacrifices we make as citizens in seeking the common good. The political process of electing good leaders and making good laws is a gift because it gives us a share in the authority that God delegates to men and women in building a just society.

In the Bible, the first three of the Ten Commandments govern our relationship with God. But the next seven outline our obligations to other people. The Epistle of James warns us that faith without works is dead (2:17), and urges us to be doers of God’s word and not hearers only (1:22). John’s Gospel says that we will know the truth, and the truth will make us free (8:32)—not comfortable, and not respected, but free in the real sense of the word: able to see and do what’s right.

To put it another way, in the Christian tradition, freedom is meant to be used in the service of others. Working to defend the dignity of human persons and the dignity of the human family is an obligation of our freedom. This is why helping the poor is so important. This is why laws that protect the unborn child, the immigrant, and the disabled are so vital. St. Augustine wrote that the state not governed by justice is no more than a gang of thieves. So it’s here, in the search for justice, that the Catholic citizen engages the political world. As Benedict XVI said in his encyclical Deus Caritas Est, “justice is both the aim and the intrinsic criterion of all politics.” In fact, “the just ordering of society and the State is the central responsibility of politics.”

Therefore the “separation of Church and state” can never mean that religious believers should be silent about legislative issues, the appointment of judges, or public policy. It’s not the job of the Church to run political candidates, but it’s very much the job of the Church to help Catholics think and act in accord with their faith, whether they be voters or candidates themselves. It’s very much the job of the Church to speak up for human dignity and all the best ideals on which the American experiment depends.

For Catholics, the civil order has its own sphere of responsibility and its own autonomy apart from the Church. But that doesn’t mean that civil authorities are exempt from moral engagement and criticism, either by individual believers or by the Church as a body.

This fits comfortably with the vision of the founders. What they (and the text of the First Amendment) intended was to prevent the establishment of an official state church. They never intended, and never wrote into the Constitution, any prohibition against religious believers, religious leaders, or religious communities taking an active role in public issues and the political process. The idea of exiling religion from public debate would have made no sense to them.

Our history as a nation is steeped in religious imagery, convictions, and language. The idea that we can pull those religious roots out of our political life without hurting our identity as a nation is both imprudent and dangerous. The United States is nonsectarian, and that’s important. But “nonsectarian” does not mean anti­religious, atheist, agnostic, or even fully secularized. Our public institutions flow—in large part—from a religious understanding of human rights, human nature, and human dignity.

The Church can’t be silent in public life and faithful to Jesus Christ at the same time. We need to remember that, in a democracy, working respectfully and firmly to form the public conscience violates no one’s free will.Actively witnessing to our convictions and advancing what we believe about key moral issues in public life is not “coercion.” It’s an act of truth-telling. It’s an act of honesty. It’s vital to the health of every democracy.

It’s worth recalling that the roots of the American experience are deeply Protestant, and that these roots go back a very long way, to well before the nation’s founding. Catholics have little reason to remember the Puritans fondly. But whatever one thinks of the early colonists, no one can study John Winthrop’s great 1630 sermon—written on the Atlantic Ocean as he led seven hundred souls to New England—without being moved by the zeal of the faith that produced it.

In “A Model of Christian Charity,” he told his fellow colonists, “We are a company professing ourselves fellow members of Christ. . . . [We] must love one another with pure heart fervently. We must bear one another’s burdens. . . . We must be willing to abridge ourselves of our superfluities, for the supply of others’ necessities. . . . ?We must delight in each other; make others’ conditions our own; rejoice together, mourn together, labor and suffer together, always having before our eyes our commission and community in the work, as members of the same body. So we shall keep the unity of [God’s] spirit in the bond of peace. The Lord will be our God, and delight to dwell among us, as his own people. . . . [And so we] must consider that we shall be as a city upon a hill. The eyes of all people are upon us. So that if we shall deal falsely with our God in this work we have undertaken, and so cause him to withdraw his present help from us, we shall be made a story and a byword through the world.”

That’s not a bad summary of Christian discipleship.

It’s common today—in fact, it’s too common and too easy—to see Winthrop’s vivid image of a “city upon a hill” as the root of American triumphalism. But that’s not what he imagined or intended. Winthrop meant that we would be watched, and judged, by how much we loved each other. Like it or not, our nation’s ideals are incoherent and unsustainable without their religious grounding. And as we lose that grounding, our problems become worse.

Charles J. Chaput, O.F.M. Cap., is archbishop of Philadelphia.