As bishops warn of current threats to religious liberty in the United States, Catholics can take heart that such challenges have faced them before, and they have persevered, one Church historian says.

"It's okay to realize that other people have gone on this same journey, a journey that's involved persecution, a journey that's involved a Catholic minority and a non-Catholic majority, and sometimes friction with governments," said Fr. David Endres, assistant professor of Church history and historical theology at The Athenaeum of Ohio, in an interview with CNA.

"I think it's important to remember the history, if nothing more than to realize that this is ground that has already been tread by our forefathers," he added.

"Now is the time to take heart and realize that the compass of the Scriptures and Tradition now need to be emphasized more than ever as our guide; that we cannot look to politicians, we can't look to the government, we certainly cannot look to pop culture and the media as our guide for morality."

Fr. Endres spoke with CNA during the Fortnight for Freedom, a two-week campaign by the U.S. bishops to educate Catholics about religious freedom and the current threats to the public practice of religion in the nation.

Among the threats the bishops have warned of in recent years are the contraception mandate in the Affordable Care Act, and Catholic adoption agencies being forced out of business because they will not place children with same-sex couples as mandated by state anti-discrimination laws.

The bishops recently voiced grave concerns over the Supreme Court's recent marriage decision Obergefell v. Hodges, which established same-sex marriage in all 50 states.

Although the majority opinion "makes a nod" toward religious freedom, it does not mention the First Amendment's protection of the free exercise of religion and this is very troubling, Archbishop William Lori of Baltimore told reporters on a conference call after the decision. Archbishop Lori chairs the U.S. bishops' Ad Hoc Committee on Religious Liberty.

"The free exercise of religion means that we have a right not only to debate it openly in the public square, but to operate our ministries and to live our lives in accordance to the truth about marriage without violence, or being penalized, or losing our tax exemption, or losing our ability to serve the common good through our social services and through education," he said in the June 26 conference call.

The omission of "free exercise" in the Court's majority opinion thus "could give rise to a lot of legal controversies," Archbishop Lori warned. Without guarantees of the free exercise of religion, religiously-affiliated organizations which oppose same-sex marriage and businesses who cannot serve same-sex weddings could face legal challenges.

The current threats to religious liberty – state and federal laws regulating the free exercise of religion of charitable institutions – are eerily similar to a Supreme Court case from nearly a century ago, and Catholics should take note, Fr. Endres explained.

In 1922, Oregon passed a law forcing all children between the ages of eight and sixteen in parochial and private schools into public schools. The law, the Compulsory Education Act of 1922, was supported by the Ku Klux Klan as a measure to push for standard American education and to prevent what they saw as a foreign influence – the Catholic Church – from educating immigrant children.

The Society of Sisters of the Holy Names of Jesus and Mary, along with a military private school, fought the law in court. Three years later, in Pierce v. Society of Sisters, the Supreme Court resoundingly struck down the law in a unanimous decision, ruling that it violated the freedom of parents to send their children to parochial schools.

In the history of the U.S., this was perhaps the event that bears the closest resemblance to the present-day struggle between Catholic institutions maintaining their religious freedom, and state and federal laws looking to regulate their consciences, Fr. Endres said.

However, the law is also but one incident in a U.S. history that is checkered with anti-Catholic bigotry and violence. In "Sticks, Stones, and Broken Bones: the History of anti-Catholic Violence in the U.S.", a 2014 article in Homiletic and Pastoral Review, Fr. Endres detailed just how rocky has been Catholicism's relationship with mainstream American culture.

Colonial-era laws forbade Catholics from becoming lawyers and teachers. In Maryland, Catholic parents could be fined for sending their children to Europe to receive a Catholic education. Distribution of anti-Catholic pamphlets and literature was commonplace.

Once European emigration to the U.S. increased in the 1840s and 50s, this established a largely Catholic minority of Irish and Germans.

Anti-Catholicism was mingled with xenophobia as the mainstream individualist culture was quite suspicious of Catholicism. Consequently, some U.S. residents tried to ensure that immigrants would not gain positions of power. A political party surfaced that at its root was anti-Catholic, the "Know-Nothing Party."

Convents and churches were victim to mob violence in multiple cases. Two Philadelphia parishes were burned in 1844 after rumors circulated that Catholics were trying to oust Protestant bibles from public schools.

The visit of a papal ambassador from Bl. Pius IX to report on the state of the Church in the U.S. resulted in violent unrest in multiple cities, including the burning of the ambassador's effigy.

Anti-Catholic violence waxed and waned through the years, but Catholics had never felt they fully "made it" in American society until the election of John F. Kennedy, an Irish Catholic, to the presidency. Afterward, many devout Catholics thought they would be accepted as a permanent part of the American mainstream culture.

"We felt like we had kind of come of age in this country," Fr Endres told CNA. "And that in general, we were not on the fringes."

The recent threats to religious liberty are proving more and more that this Catholic peace was a reprieve and not a permanent acceptance of Catholicism in the U.S., he added.

Why has there been so much anti-Catholic sentiment in the United States? The overall conflict between the Church and American culture has centered on freedom and authority, and the fault line still exists today, Fr. Endres explained.

"I would say part of it is the role of individuals vis a vis community and the Church has always upheld quite a communal emphasis," he said. Historically, the mainstream American culture promoted individualism, and looked down on Catholics who followed the authority of the Bishop of Rome.

This conflict also extends to the debate of the role of community versus the freedom of the individual, he added.

"We have this strange idea that's developed in this country that freedom means absolute autonomy of persons. And the Church has never believed that true freedom consisted of absolute autonomy, but instead, basically a relationship with God and with one another. We kind of have this path set before us that yes, we are responsible to other people. We are responsible to God in a special way, and absolute autonomy has no place in that kind of worldview."

Historically, this played out in the Protestant individualistic culture of the U.S. against the Catholic view of community and authority.

This push for absolute autonomy has played out in the push for acceptance of same-sex marriage and of the transgender movement.

On the other side is a Christian anthropology, he said: "how we view our being made in the image and likeness of God, how we view marriage and family life, gender, sexuality, all those kinds of things."

The question then becomes, "do I have an obligation to anyone but myself?" Fr. Endres asked rhetorically.

"The modern notion would be 'it's just you,'" whereas a Christian recognizes that he has an obligation to obey and love God and the Church, and to love his neighbor.

And Catholics are once again being moved to the margins, with laws prohibiting them from publicly practicing their religion and remaining true to Church teaching on sexuality.

However, "it's important for us to realize then that to be on the margins of society is not always a bad thing," he added.

The present hostility to Catholic teaching on sexuality might actually be a "call instead to remain faithful on the margins," he said, because the Catholic faith is counter-cultural.

"We are speaking a truth that is not always popular, but which we believe very strongly comes from Christ and more broadly from the revelation of God to man. And if you really believe that, you can't accommodate."

Throughout U.S. history, some Catholics have remained faithful to the Church, while others accommodated to the culture. For example, some German Catholic immigrants and priests in the 19th century left the Church to become Protestant because they couldn't endure the anti-Catholic hostility.

"Americanists," the subjects of the 1899 encyclical Testem benevelentiae nostrae of Leo XIII, were American Catholics who had been so affected by the American culture that they were no longer authentically Catholic. This problem exists today.

"Americanism shows that more or less constant feature of American Catholic history, where Catholics have to make that choice of whether they are going to identify primarily as American, and then Catholic secondarily, or Catholic as a primary identity and American as a second," Fr. Endres said.

"So what's going to be the noun, and what's going to be the adjective?"